1
Q
The Cardiovascular system consists of the following structures:
A
- HEART
- ARTERIES
- VEINS
- CAPILLARIES
- The LYMPHATICS
2
Q
Cardiovascular system: Functions
A
- Transport of oxygen and nutrients to the tissues
- Transport of carbon dioxide and other metabolic waste products from the tissues
- Temperature regulation
- Distribution of molecules (eg. Hormones and cells)
3
Q
Functional components of the Cardiovascular System:
A
- Blood vascular system
2. Lymph vascular system
4
Q
3 Basic Components of Cardiovascular System:
A
- Endothelium- lining of the inner surface of the cardiovascular system
- Smooth Muscles- capillaries and post capillaries venules does not have.
- Connective Tissue- made up of collagen, elastic fibers
ground substance of glycolproteins and proteoglycans.
Influenced by:
mechanical factors – BP
metabolic factors – local needs
5
Q
3 Layers of the 4 Chambers:
A
- Endocardium
- Myocardium
- Epicardium
6
Q
Endothelium(simple squamous) –endothelial cells
- subendocardium : thick loose c.t.
- Purkinje fibers
A
ENDOCARDIUM
7
Q
- modified cardiac muscle
- decrease number of myofibrils limited to the periphery
- lack transverse tubules
- larger diameter
- more sarcoplasm and glycogen(pale)
- rounded nuclei in groups of 2 or more
A
Purkinje fibers
8
Q
thickest and most prominent layer, with strands of connective tissue and vascular network in between cells
A
MYOCARDIUM
9
Q
• striated, involuntary
• cylindrical / elongated, w/ branching ends
• mono- / binucleated
*INTERCALATED DISCS —transverse lines at the ends of the branching fibers
A
Cardiac Muscle Tissue
10
Q
INTERCALATED DISCS
A
- Fascia adherens / junctions - most prominent; anchoring sites
- Desmosomes / Macula adherens - cardiac cells binding
- Gap junction - ionic continuity
* Intercalated disc- found at the branches of the muscle
11
Q
- visceral layer of pericardium mesothelial cells-outer surface, secretes lubricating fluid
- fluid is used so that visceral and parietal pericardium can slide freely during contraction of the heart
A
EPICARDIUM
12
Q
- contain blood vessels, nerves, and fat cells
- pericardial cavity and sac
A
subepicardium
13
Q
Muscles of the Heart
A
- Trabecula carnae- it is found arising from both ventricles.
- Papillary muscle- extension of the ventricular myocardium, it is where the corda tendinae are attached.
- Chorda tendinae- connect flops of AV to the wall of the
heart.
14
Q
CARDIAC SKELETON (Dense Irregular Connective Tissue)
A
- Septum membranaceum - IVS; muscle attachments
- Trigonafibrosa - between arterial foramina and AV
canals - Annuli fibrosi - principal attachment for the cardiac
muscles and Atrioventricular valves
15
Q
Functions of Cardiac Skeleton
A
- Anchors and supports heart valves
- Firm points of insertion for cardiac muscles
- Acts as electrical insulation between atria and ventricles
16
Q
- is the central or main supporting structure of the heart. Though called skeleton, it is not made of bones but of dense irregular connective tissue.
A
Cardiac skeleton
17
Q
Impulse Conducting System
A
- SA Node - pacemaker of the heart ; sulcus terminalis
area - AV node – below posterior leaf of aortic valve
- Bundle of His – trigonumfibrosumdextrus
- Right and Left branches
- Subendocardial network of PF
18
Q
Blood vessels of the heart
A
coronary arteries > cardiac veins > coronary sinuses >rt atrium
19
Q
Lymphatics of the Heart:
A
- Grooves of the heart
- Epicardial connective tissue
- Myocardium and Endocardium
20
Q
It is a serious complication of rheumatic fever. It is a bacterial infection of streptococcus, in which it affects the upper respiratory tract and extends to the heart. It targets the heart valves.
A
Rheumatic Heart Disease
21
Q
- narrowing of the lumen of the blood vessel, supplying the heart due to Atherosclerosis. Fat are deposited in the lumen called plaque. It decreases nutrients, oxygen until it completely obstructs causing
A
Coronary Heart Disease
22
Q
- cardiac myocytes shrunken, pyknotic nuclei; dense, cloudy cytoplasm.
- coagulation necrosis
- loss of nuclei
- absence of striations
- fibrous scar
A
Myocardial Infarct
23
Q
- tubular structures that convey blood away and towards the heart
A
BLOOD VESSELS
24
Q
BLOOD VESSELS
A
Arteries : toward organ and tissue
Capillaries : anastomosing channels of small caliber vessels providing interchange of substances.
Veins : return blood to the heart
25
COMMON BASIC STRUCTURE
Tunica intima - innermost part, analogue in heart is
endocardium
Tunica media - middle part, analogue in heart is
myocardium
Tunica adventitia - outermost part, analogue in heart is
epicardium
26
Endothelium = layer of endothelial cells
Subendothelium = Loose Connective Tissue with smoothmuscle cells
*Internal elastic lamina/membrane or fenestrated membrane of Henle
* scalloped appearance
Tunica intima
27
- Circumferentially arranged smooth muscles, with elastic, collagen fibers III, glycoproteins and proteoglycans
* External elastic lamina/membrane
Tunica media
28
separates the Tunica media from Tunica adventitia in arteries
External elastic lamina/membrane
29
- Loose Connective Tissue
- Type I collagen and elastic fibers Vasa vasorum,
nervi vasorum
- Vasa vasorum: blood supply of blood vessel (vessel of
the vessel)
- Nervi vasorum: nerve supply of blood vessel
(VASOMOTOR – noerepinephrine)
- Subendothelium: With fibroblasts and Myointimal cells
- Early changes of atherosclerosis
Tunica adventitia
30
Endothelial cells 1
1. Acts as permeability barrier
2. Basement membrane maintenance – synthesize collagens and proteoglycans
3. Fc VIII (Von Willebrand) secretion – protective thrombus formation
4. Minimize pathological thrombus – synthesize and secrete prostacyclin, thrombomodulin, NO2 (inhibits platelet adhesion )
31
Endothelial cells 2
5. Controls blood flow – secrete vasoactive
Factors:
*VD - prostacyclin, NO2
*VC – endothelin
6. Mediate acute inflammatory reaction – produce IL 1,6,8 (cell adhesion molecules)
7. Produce growth factors – fibroblast GF, platelet-derived GF, blood colony stimulating factor
32
Arteries
1. Large / Elastic / Conducting
2. Medium / Muscular / Distributing
3. Small
* Arterioles
* Pre-capillary (Metarterioles)
33
Artery vs Vein
Artery- Tunica Media is thickest; it is a high pressure vessel
Vein- Tunica Adventitia is the thickest; it is a low pressure vessel
34
conducting / elastic arteries (aorta,pulmonary artery)
1. Intima
a. endothelium- simple squamous
b. subendothelium- thin loose CT
c. indistinct IEL or Henle’s membrane –fenestrated sheet of elastin
2. Media- thickest, many elastic lamellae alternating with smooth muscles
3. Underdeveloped adventitia with vasa vasorum
Large arteries
35
Medical Application: Arteries
1. arteriosclerosis – hardening of arteries
2. atherosclerosis – fibrous deposits(atheroma)
3. aneurysm – dilatation /weakening (wall)
36
- thickening of Tunica intima
- deposition of lipid and fibrous material
- plaque or atheroma
- scarring/ calcification of wall
- mainly associated with elastic artery and coronary artery
Atherosclerosis
37
Remember (Large Arteries)
*Large Arteries- large amounts of elastic fibers; check the Tunica Media as identification as is it very thick, while the Tunica Adventitia is underdeveloped
38
- distributing / muscular arteries
1. Intima - prominent” Internal elastic lamina
2. Media - “External elastic lamina”--- wavy fenestrated lamella of elastic fibers; separates media from adventitia
3. Adventitia - Loose Connective Tissue
* vasa vasorum , nervi vasorum
Medium sized arteries
39
- (Arterioles / transitional arterioles / precapillary or metarteriole)
- isolated spirally arranged smooth muscle fibers; no EEL
* * 1-2 layers
- 1.0-.1 mm diameter
- regulate distribution of blood to the capillary beds
- Maintain blood pressure
Small arteries/resistance arteries
40
- thin walled tubes which branches extensively
- Smallest, No smooth muscle
* PERICYTES only(contractile cells)
- layers: tunica intima –single layer of endothelial cells with thin tunica adventitia
* microcirculation
* exchange metabolites by diffusion to and from cells
* accommodate 1-2 RBC only (>2---venule)
Capillaries : (90%)
41
are common on capillaries and on postcapillary venules
Pericytes (Rouget cells)
42
MICROCIRCULATION: Types of flow
1. Nutritional flow
| 2. Non-nutritional / shunt flow – metarteriole
43
MICROCIRCULATION: Types of capillary
1. True capillary
| 2. Thoroughfare/preferential channels
44
Functions of the microcirculation
1. Regulate blood flow and tissue perfusion
2. Regulate blood pressure
3. Regulate tissue fluid (swelling or edema)
4. Delivery of oxygen and other nutrients and removal of CO2 and other metabolic waste products
5. Regulate body temperature
6. Role in inflammation.
45
Types of Capillary (according to wall structure)
1. Continuous
2. Fenestrated
3. Sinusoidal
46
- complete layer
- lack of pore
- in muscle, exocrine glands, lungs, skin and nervous
tissue
Continuous
47
- with pores or fenestrae
- found in kidney, intestine, choroid plexus and endocrine
glands
** diaphragm
Fenestrated
48
- tortuous path and greatly enlarged diameter
- absence of continuous basal lamina and lining in walls
- presence of multiple fenestrations and phagocytes in liver
and hematopoietic organs
***Sinuses - barrel-like arrangement of cells
- spleen
Sinusoidal
49
Exchange in continuous capillary:
1. Passive diffusion
2. Pinocytic vesicles
3. Intercellular junctions
50
- capacitance / reservoir / compliance vessels
- larger caliber , thinner walls than arteries
- more collagen 70% TBV
Veins
51
3 Layers of the Vein
Tunica Adventia– collagenous connective tissue in large amount
Tunica Media– sparse circular muscle loosely arranged
Tunica Intima – endothelial layer
52
- Postcapillary, collecting and muscular venules drain
capillary beds
- site of leukocyte
- exit from vasculaturelarge lumen, very thin wall
- 2-3 layers smooth muscles
Small Veins
53
- 3-5 layers smooth muscles
| - with valves
Medium size veins
54
- prominent VALVES
- >5 layers smooth muscles
- Vena cava
Large muscular vein
55
- smallest, union of capillaries
- sluggish flow
- no smooth muscle
- main site of WBC migration into and out of circulation
Post-capillary venules
56
larger, more pericytes
Collecting venules
57
- larger
| - smooth muscle layer
Muscular venules
58
The venous system: Control of flow
1. pressure gradient
2. skeletal muscles
3. valves (veins >2 mm)
59
- bundled longitudinal smooth muscle
- prominent VALVES
- SVC and IVC
Large veins
60
Medical application: VEINS
a. Thrombophebitis– occlusion and swelling
b. Varicosities – wall weakness, luminal P, valve defects
Eg. Saphenous vein, hemorrhoids, esophageal varices, varicocele
61
Special veins
No smooth muscle – cerebral, meningeal, dural sinuses, retina, penis, placenta
Rich in smooth muscle – gravid uterus, limbs, umbilical, mesenteric
62
ALTERNATIVE PATHWAYS
1. Portal system – (cap > veins > cap > circulation)
Venous – hepatic portal system (Liver)
hypothalamo-hypophyseal portal system
Arterial – Kidney
- afferent arteriole--cap—efferent arteriole
2. A-V shunt – (glomus) - fingers, nailbeds, ears, nose
skin - temperature regulation and heat conservation
63
```
Lumen: smaller
Thickness of wall: thicker
Thickest coat: Tunica media
Rigidity of wall: More rigid
Internal elastic membrane: present
Valves: absent
Muscles and elastic tissue: More abundant
Vasa vasorum: Extend up to tunica media
```
Artery
64
```
Lumen: bigger
Thickness of wall: Thinner
Thickest coat: Tunica adventitia
Rigidity of wall: Less rigid
Internal elastic membrane: absent
Valves: present
Muscles and elastic tissues: Less abundant
Vasa vasorum: Extend up to tunica intima
```
Vein
65
- exits the artery, enters the veins
- no RBC ; with granulocytes and lymphocytes
- microcirculation - 2% of plasma exchange
Lymph Vascular System
66
- more permeable (thin endothelium)
- no basement membrane
- no pericytes have anchoring filaments
- have valves
- reticulin fibers/scanty ground substance
- capillaries---vessels---ducts
Lymphatic vessels
67
Layers of the Lymphatic vessel
1. intima
2. media
3. adventitia
68
Two Main Vessels:
1. thoracic duct
| 2. right lymphatic duct
69
Lymphatics found in almost all organs except:
CNS, bone marrow, coats of eyes, internal ear, placenta, bone, cartilage, epithelia, thymus, teeth
70
Lymphatic flow aided by:
Intrinsic forces
- lymphangions
- smooth ms (collecting vessels)
Extrinsic forces
- contraction – skeletal ms
- VALVES---- keeps lymph flow “unidirectional”
71
```
Sx
- facilitate spread
o Pathogens
o Parasites
o malignant cells
```
lymph edema
72
- the act of supporting an unconscious patient's breathing and circulation in order to preserve their life and buy time for professional emergency medical attention
BLS (BASIC LIFE SUPPORT)
73
- set of clinical interventions for the urgent treatment of cardiac arrest, stroke and other life-threatening medical emergencies, as well as the knowledge and skills to deploy those interventions
ACLS (ADVANCED CARDIOVASCULAR LIFE SUPPORT)
74
IHCAs
In-Hospital Cardiac Arrests
75
OHCAs
Out of Hospital Cardiac Arrests
76
IHCA: Chains of Survival
1. Surveillance and Prevention
2. Recognition and activation of emergency response system
3. Immediate high-quality CPR
4. Rapid Defibrillation
5. Advance life support and postarrest care
77
OHCA: Chains of Survival
1. Recognition and activation of emergency response system
2. Immediate high-quality CPR
3. Rapid Defibrillation
4. Basic and advance medical services
5. Advance life support and postarrest care
78
Places where Cadiac Arrest happen
1. Airports
2. Malls/markets
3. Schools
4. Municipal halls
5. Streets
6. Homes
79
Untrained lay rescuers should provide __ for adult victims of cardiac arrest - until the arrival of an AED or rescuers with additional training.
compression-only (Hands-Only) CPR
80
In adult victims of cardiac arrest, perform
chest compressions - 100 to 120/min
81
The number of chest compressions/per minute an important determinant :
1. return of spontaneous circulation (ROSC)
| 2. survival with good neurologic function.
82
The actual number of chest compressions / minute:
1. rate of chest compressions
2. number and duration of interruptions
a. to open the airway
b. deliver rescue breaths
c. allow AED analysis
83
Additional components of high-quality CPR:
1. allowing complete chest recoil after each compression
| 2. avoiding excessive ventilation
84
Chest Compression Depth
depth of at least 2 inches (5 cm)
85
Compressions create blood flow by:
1. increasing intrathoracic pressure
2. directly compressing the heart
>results in critical blood flow
>oxygen delivery to the heart and brain
86
High-quality CPR performance targets:
1. compressions of adequate rate and depth
2. Allowing complete chest recoil between compressions *
3. Minimizing interruptions in compressions,
4. avoiding excessive ventilation.
* rescuers must avoid leaning on the chest between compressions
87
Chest wall recoil creates:
(-) intrathoracic Pressure
promoting:
a. venous return
b. cardiopulmonary blood flow
88
Incomplete recoil
- Increase intrathoracic Pressure
- Reduces venous return, coronary perfusion pressure, and myocardial blood flow
- influence resuscitation outcomes
89
All patients who progress to brain death or circulatory death after initial cardiac arrest should be considered __.
potential organ donors
90
TTM cooling to temperatures between __
= improvement in neurologic outcome for those in whom hypothermia was induced.
32°C and 34°C
91
Cardiac Arrest in Pregnancy: Emergency Cesarean Delivery
In situations such as nonsurvivable maternal trauma or prolonged maternal pulselessness, in which maternal resuscitative efforts are obviously futile >>>
perimortem cesarean delivery (PMCD) should be considered at 4 minutes after onset of maternal cardiac arrest or resuscitative efforts
92
Why perimortem cesarean delivery (PMCD)?
- provides separate resuscitation
| - the ultimate relief of aortocaval compression, which may improve maternal resuscitation outcomes
93
Pediatric Basic Life Support and CPR
1. Reaffirming the C-A-B sequence as the preferred sequence for pediatric CPR
2. Establishing an upper limit of 6 cm for chest compression depth in an adolescent
3. Mirroring the adult chest compression rate of 100 to 120/min
4. Strongly reaffirming that compressions and ventilation are needed for pediatric BLS
94
Pediatric chest compression technique
- 2 thumb– encircling hands
| - compression-to-ventilation ratio (3:1 with 90 compressions and 30 breaths per minute)
95
- otherwise known as the “CPR Training in Schools Act” - was approved on Sept. 15, 2015 by the Committee on Basic Education and Culture headed by Rep. Kimi Coseteng (5th District, Pangasinan)
- Authored by Cong. Yeng Guiao – “Samboy Lim Act”
House Bill No. 5891
96
Background (CPR)
Bystander CPR is a vital intervention before arrival of emergency services
Early resuscitation and prompt defibrillation (within 1-2 minutes) can result in >60% survival
97
- Occurs shortly after the heart stops in up to 40% of cardiac arrests
- Described as barely, heavy, noisy or gasping breathing
- Recognise as a sign of cardiac arrest
Abnormal Breathing
98
Chest Compression
- Place the heel of one hand in the centre of the chest
- Place other hand on top
- Interlock fingers or avoid putting pressure on the side of the chest
Compress the chest
Rate 100 – 120 min-1
Depth 5 – 6 cm
- Equal compression : relaxation
- When possible change CPR operator every 2 min
99
Rescue Breaths
- Pinch the nose
- Take a normal breath
- Place lips over mouth
- Blow until the chest rises
- Take about 1 second
- Allow chest to fall
- Repeat
100
CPR in children
- Adult CPR techniques can be used on children
| - Compressions at least 1/3 of the depth of the chest
101
AED in Children
Age > 8 years - use adult AED
Age 1-8 years - use paediatric pads / settings if available (otherwise use adult mode)
Age
102
CPR
1. Approach safely
2. Check response
3. Shout for help
4. Open airway
5. Check for breathing
6. Call 911
7. 30 chest compression
8. 2 rescue breaths
103
AED
1. Approach safely
2. Check response
3. Shout for help
4. Open airway
5. Check for breathing
6. Call 911
7. Attach AED
8. Follow voice prompts
104
The first sign of development is the formation of the __ in the ventral wall of the primitive
foregut during week 4
respiratory diverticulum
105
The distal end of the respiratory diverticulum enlarges to form the lung bud. The lung bud divides into two bronchial buds that branch into the__.
main (primary), lobar (secondary), segmental (tertiary), and subsegmental bronchi
106
The respiratory diverticulum initially is in open communication with the foregut, but eventually they become separated by indentations of mesoderm, the __.
tracheoesophageal folds
107
When the tracheoesophageal folds fuse in the midline to form the tracheoesophageal septum, the foregut is divided into the __.
trachea ventrally and esophagus dorsally
108
The laryngeal epithelium and glands are derived from __.
endoderm
109
The laryngeal muscles are derived from somitomeric __ of pharyngeal arches 4 and 6.
mesoderm
110
The tracheal epithelium and glands are derived from __.
endoderm
111
The tracheal smooth muscle, connective tissue, and C-shaped cartilage rings are derived from visceral __.
mesoderm
112
- is an abnormal communication between the trachea and esophagus that results from improper division of foregut by the tracheoesophageal septum.
- It is generally associated with esophageal atresia and polyhydramnios.
Tracheoesophageal fistula
113
This is the most common type, occurring in 82% of cases.
Esophageal atresia with a tracheoesophageal fistula at the distal one-third end of the trachea
114
Development of the lungs
1. Pseudoglandular period (weeks 7–16)
2. Canalicular period (weeks 16–24)
3. Terminal sac period (week 24 to birth)
4. Alveolar period (week 32–age 8 years)
115
During this period, the developing lung resembles an exocrine gland. The numerous endodermal tubules (ETs) are lined by simple columnar epithelium and are surrounded by mesoderm containing a modest capillary network. Each endodermal
tubule branches into 15–25 terminal bronchioles (TBs). During this period, respiration is not possible, and premature infants cannot survive.
Pseudoglandular period (weeks 7–16)
116
During this period, the TBs branch into three or more respiratory bronchioles (RBs). The respiratory bronchioles subsequently branch into three to six alveolar ducts (ADs). The terminal bronchioles, respiratory bronchioles, and alveolar ducts are now lined by a simple cuboidal epithelium and are surrounded by mesoderm containing
a prominent capillary network. Premature infants born before week 20 rarely survive.
Canalicular period (weeks 16–24)
117
During this period, terminal sacs (TSs) bud off the ADs and then dilate and expand into the surrounding mesoderm.
The terminal sacs are separated from each other by primary septae. The simple cuboidal epithelium within the terminal sacs differentiates into type I pneumocytes
(thin, flat cells that make up part of the blood–air barrier) and type II pneumocytes (which produce surfactant).
Premature infants born between week 25 and week 28 can survive with intensive care
Terminal sac period (week 24 to birth)
118
During this period, terminal sacs are partitioned by secondary septae to form adult alveoli. About 20–70 million alveoli are present at birth. About 300–400 million
alveoli are present by 8 years of age. The major mechanism for the increase in the number of alveoli is formation of secondary septae that partition existing alveoli.
After birth, the increase in the size of the lung is due to an increase in the number of respiratory bronchioles. On chest radiographs, lungs of a newborn infant are denser than an adult lung because of the fewer number of mature alveoli
Alveolar period (week 32–age 8 years)
119
- provides for exchange of O2 and CO2 to and from the blood
respiratory system
120
Functionally, the system has two components:
■ The conducting portion - which consists of the nasal
cavities, nasopharynx, larynx, trachea, bronchi (Gr.
bronchos , windpipe), bronchioles, and terminal bronchioles
■ The respiratory portion - where the system’s main function of gas exchange occurs, consisting of respiratory
bronchioles, alveolar ducts, and alveoli
121
The left and right nasal cavity each has two components:
the external, dilated vestibule and the internal nasal cavity .
122
__ enters the nares (nostrils) partway into the vestibule and has sweat glands, sebaceous glands, and coarse, moist vibrissae (hairs) that fi lter out particulate material from the inspired air.
Skin of the nose
123
Lining epithelium of the Nostril
Stratified squamous keratinized epithelium
124
Within the vestibule, the epithelium loses its keratinized nature and undergoes a transition to typical __ before entering the nasal cavities.
pseudostratified columnar epithelium
125
Th e nasal cavities lie within the skull as two cavernous
| chambers separated by the osseous __
nasal septum
126
Extending from each lateral wall are three bony shelflike projections called __.
conchae or turbinates
127
Th e middle and inferior conchae are covered with respiratory epithelium; the roof of the nasal cavities and
the superior conchae are covered with specialized __
olfactory epithelium
128
Most of the nasal cavities and the respiratory system’s conducting portion is lined with mucosa having ciliated __ and commonly known as respiratory epithelium
pseudostratified columnar epithelium
129
The respiratory epithelium has five major cell types, all of
| which contact an unusually thick basement membrane:
1. Ciliated Columnar Cells
2. Goblet cells
3. Brush Cells
4. Small granule cells or Kulchitsky Cells
5. Basal Cells
130
- are the most abundant, each with 250-300 cilia on its apical surface
- contacts with the lumen
Ciliated columnar cells
131
- are also numerous and predominate in some areas, with basal nuclei and apical domains filled with granules of mucin glycoproteins
- provides mucus
Goblet cells
132
- are a much less numerous, columnar cell
type, in which a small apical surface bears sparse, blunt
microvilli
- are chemosensory receptors resembling gustatory cells, with similar signal transduction components and synaptic contact with afferent nerve endings on their basal surfaces.
Brush cells
133
- are difficult to distinguish in routine preparations, but possess numerous dense core granules 100 to 300 nm in diameter. Like enteroendocrine cells of the gut, they are part of the diffuse neuroendocrine system (DNES). Like brush cells, they represent only about 3% of the cells
in respiratory epithelium.
Small granule cells (or Kulchitsky cells)
134
- are mitotically active stem and progenitorcells that give rise to the other epithelial cell types.
Basal cells
135
The chronic presence or accumulation of toxins that
occur with heavy cigarette smoking or industrial air
pollution affects the respiratory epithelium beginning
in the nasal cavities. Immobilization of the cilia causes
failure to clear mucus containing filtered material and
exacerbates the problem, leading eventually to the
likelihood of __ of the epithelium.
A change from pseudostratified ciliated columnar to
stratified squamous epithelium can occur, particularly in
the mucosa of bronchi. This can produce precancerous
cell dysplasia in this tissue.
squamous metaplasia
136
The olfactory chemoreceptors for the sense of smell are located in the __, a specialized region of the mucous membrane covering the superior conchae at the roof of the nasal cavity.
olfactory epithelium
137
3 Cell Types of Olfactory Epithelium
1. Olfactory Neurons
2. Supporting Cells or Sustentacular Cells
3. Basal Cells
138
- are bipolar neurons present throughout this epithelium. Their nuclei form an irregular row near the middle of this thick epithelium. The apical (luminal) pole of each olfactory cell is its dendrite end and has a knoblike swelling with about a dozen basal bodies. From the basal bodies emerge long cilia with nonmotile axonemes but considerable surface areas for membrane chemoreceptors.
Olfactory neurons
139
- are columnar, with broad, cylindrical
apexes containing the nuclei and narrower bases.
- On their free surface are microvilli submerged in a fluid layer. Well-developed junctional complexes bind the supporting cells to the olfactory cells.
- The supportive role of these cells is not well understood, but they express abundant ion channels that help maintain a microenvironment conducive to olfactory function and survival.
Supporting cells
140
- are small, spherical or cone-shaped cells near the basal lamina. These are the stem cells for the other two types, replacing the olfactory neurons every 2 to 3 months and support cells less frequently.
Basal cells
141
The lamina propria of the olfactory epithelium possesses
large serous glands, the __, which produce a constant flow of fluid surrounding the olfactory cilia and facilitating the access of new odoriferous substances.
olfactory glands (of Bowman)
142
The loss or reduction of the ability to smell,__, respectively, can be caused by traumatic damage to the ethmoid bone that severs olfactory nerve axons or by damage to the olfactory epithelium caused by intranasal drug use.
anosmia or hyposmia
143
- are bilateral cavities in the frontal, maxillary, ethmoid, and sphenoid bones of the skull
- They are lined with a thinner respiratory epithelium with fewer goblet cells.
- The lamina propria contains only a few small glands and is continuous with the underlying periosteum
- communicate with the nasal cavities through small openings; mucus produced there is moved into the nasal
passages by the activity of the ciliated epithelial cells.
paranasal sinuses
144
Chronic sinusitis and bronchitis are components of primary ciliary dyskinesia, or __, an inherited genetic disorder characterized by defective ciliary action.
Kartagener syndrome
145
The nasal cavities open posteriorly into the __, which is the first part of the pharynx and continuous caudally with the oropharynx, the posterior part of the oral cavity leading to the larynx.
nasopharynx
146
Lining epithelium of Nasopharynx and Oropharynx
Nasopharynx - Respiratory Epithelium
| Oropharynx. - Stratified squamous nonkeratinized epithelium
147
Lamina Propria of the Nasopharynx contains some serous and mucous glands with the presence of large masses of lymphoid tissue that forms a component of __ protecting the entry portals of the respiratory and gastrointestinal systems.
This lymphoid tissue is particularly prominent in children and young adults and usually bulges outwards into the lumen of the nasopharynx, producing an appearance similar to that seen in the lingual tonsil with epithelial crypts. This is called the nasopharyngeal tonsil or adenoid.
Waldeyer ring of lymphoid tissue
148
- is a short (4 cm X 4 cm) passage for air between the pharynx and the trachea.
- Its rigid wall is reinforced by hyaline cartilage (in the thyroid, cricoid, and the inferior arytenoid cartilages) and smaller elastic cartilages (in the epiglottis, cuneiform, corniculate, and the superior arytenoid cartilages), all of which are connected by ligaments. In addition to maintaining an open airway, movements of these cartilages by skeletal muscles participate in sound production during phonation.
larynx
149
- Lined by Pseudostratified ciliated columnar epithelium with goblet cells
- immovable
- Also known as Venticular Fold
- contain seromucous gland, lymphoid nodule
False vocal cord
150
- Stratified squamous non-keratinizing epithelium due to “wear and tear”
- has no seromucous gland
- participate in sound production
- has vocalis muscle
True Vocal Cord
151
- a flattened structure projecting from the upper rim of the larynx, serves to prevent swallowed food or fluid from entering that passage
epiglottis
152
Parts of Epiglottis
1. Laryngeal surface basal part – pseudostratified ciliated columnar epithelium
2. Lingual surface upper part – stratified squamous nonkeratinizing epithelium; closes at laryngeal; exposed to food
153
Deep to the mucosa of each vocal fold are large bundles
| of striated fibers that comprise the __.
vocalis muscle
154
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During phonation the vocalis muscles draw the paired vocal
folds together (adduction), narrowing the intervening luminal space,__, and air expelled from the lungs causes the adducted vocal folds to vibrate and produce sound.
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the rima glottidis
155
Inflammation of the larynx, or __, is due to viral infection and is usually accompanied by edema or swelling of the organ’s lamina propria. This changes the shape of the vocal folds or other parts of the larynx, producing hoarseness or complete loss of voice.
laryngitis
156
Benign reactive polyps, called __, are frequent in the stratified squamous epithelium of the true vocal cords, affecting the voice.
singer’s nodules
157
- 10 to 12 cm long in adults, is lined with typical respiratory
mucosa in which the lamina propria contains numerous
seromucous glands producing watery mucus.
- A series with about a dozen C-shaped rings of hyaline cartilage
- The open ends of the cartilage rings are on the posterior surface, against the esophagus, and are bridged by a bundle of smooth muscle called the trachealis muscle and a sheet of fibroelastic tissue attached to the perichondrium.
- The entire organ is surrounded by adventitia.
trachea
158
- relaxes during swallowing to facilitate the passage of food by allowing the esophagus to bulge into the lumen of the trachea, with the elastic layer preventing excessive distention of the lumen.
- The muscle strongly contracts in the cough reflex to narrow the tracheal lumen and provide for increased velocity of the expelled air and better loosening of material in the air passage.
trachealis muscle
159
The trachea divides into two __ that enter each lung at the hilum, along with arteries, veins, and lymphatic vessels.
primary bronchi
160
After entering the lungs, the primary bronchi course
downward and outward, giving rise to three __ in the right lung and two in the left lung, each of which supplies a pulmonary lobe.
secondary (lobar) bronchi
161
These lobar bronchi again divide, forming tertiary (segmental) bronchi. Each of the tertiary bronchi, together with the smaller branches it supplies, constitutes a __—approximately 10% to 12% of each lung with its own connective tissue capsule and blood supply.
bronchopulmonary segment
162
The tertiary bronchi give rise to smaller and smaller
| bronchi, whose terminal branches are called __.
bronchioles
163
Each bronchiole enters a pulmonary lobule, where it branches to form five to seven __.
terminal bronchioles
164
The __ are each pyramid-shaped, with the apex aimed at the pulmonary hilum, and each is delineated by a thin layer of connective tissue, which in adults is frequently incomplete.
pulmonary lobules
165
Each __ repeatedly, with each branch becoming progressively smaller until it reaches a diameter of 1 to 2 mm. The mucosa of the larger bronchi is structurally similar to the tracheal mucosa except for the organization of cartilage and smooth muscle.
primary bronchus branches
166
In the __ most cartilage rings completely encircle the lumen, but as the bronchial diameter decreases, cartilage rings are gradually replaced with isolated plates of hyaline cartilage. Small mucous and
serous glands are abundant, with ducts opening into the bronchial lumen. The lamina propria also contains crisscrossing bundles of spirally arranged smooth muscle and elastic fibers, which become more prominent in the
smaller bronchial branches.
primary bronchi
167
- Respiratory Epithelium
- Prominent spiral bands of smooth muscle; irregular hyaline cartilage plates
- Repeated branching; conduct air deeper into lungs
Bronchi
168
- Simple ciliated cuboidal to columnar, with Clara cells
- Prominent circular layer of smooth muscle; no cartilage
- Conduct air; important in bronchoconstriction and bronchodilation
Bronchioles
169
- Simple cuboidal, ciliated and Clara cells
- Thin, incomplete circular layer of smooth muscle; no cartilage
- Conduct air to respiratory portions of lungs; Clara cells with several protective functions
Terminal bronchioles
170
- Simple cuboidal, ciliated and Clara cells, with scattered
alveoli
- Fewer smooth muscle fibers, mostly around alveolar openings
- Conduct air deeper, with some gas exchange and protective Clara cells
Respiratory bronchioles
171
- Simple cuboidal between many alveoli
- Bands of smooth muscle around alveolar openings
- Conduct air, with much gas exchange
Alveolar ducts and sacs
172
- Types I and II alveolar cells (pneumocytes)
- None (but with network of elastic and reticular fibers)
- Sites of all gas exchange; surfactant from type II pneumocytes; dust cells
Alveoli
173
- are typically designated as the intralobular airways with diameters of 1 mm or less, formed after about the 10th generation of branching; they lack both mucosal glands
and cartilage, although dense connective tissue is associated with the smooth muscle
Bronchioles
174
In the larger bronchioles, the epithelium is still ciliated pseudostratified columnar, but this decreases in height and complexity to become ciliated simple columnar or simple cuboidal epithelium in the smallest __, which are the last parts of the air conducting system.
terminal bronchioles
175
The ciliated epithelial lining of bronchioles begins the __, important in clearing debris and mucus by moving it upward along the bronchial tree and trachea.
mucociliary apparatus or escalator
176
Most numerous in the cuboidal epithelium of terminal
| bronchioles are __, which have nonciliated, dome-shaped apical ends with secretory granules
Clara cells, or exocrine bronchiolar cells
177
Clara cells have various functions, including the following:
■ Secretion of surfactant lipoproteins and mucins in the
fluid layer on the epithelial surface
■ Detoxification of inhaled xenobiotic compounds by
enzymes of the SER
■ Secretion of antimicrobial peptides and cytokines for
local immune defense
■ In a stem cell subpopulation, injury-induced mitosis
for replacement of the other bronchiolar cell types
178
The bronchiolar lamina propria still contains elastic fibers
and smooth muscle, producing folds in the mucosa. Muscular contraction in both the bronchi and the bronchioles is controlled primarily by nerves of the __.
autonomic nervous system
179
Each __ subdivides into two or more respiratory
bronchioles that include saclike alveoli and represent,
therefore, the first-part respiratory region of this organ system.
- The mucosa lining consists of Clara cells and ciliated cuboidal cells, with simple squamous cells at the alveolar openings and extending into the alveolus.
terminal bronchiole
180
Distal ends of respiratory bronchioles branch into tubes called __ that are completely lined by the openings of alveoli. Both the alveolar ducts and the alveoli themselves are lined with extremely attenuated squamous cells. In the thin lamina propria, a strand of smooth muscle cells surrounds each alveolar opening and a matrix of elastic and collagen fibers supports both the duct and its alveoli
alveolar ducts
181
Larger clusters of alveoli called __ form the
ends of alveolar ducts distally and occur occasionally along
their length.
- The lamina propria is now extremely thin, consisting essentially of a network of elastic and reticular fibers that encircles the alveolar openings and closely surrounds each alveolus.
- Prominent in this sparse connective tissue, another network of capillaries also surrounds each alveolus.
alveolar sacs
182
- are saclike evaginations, each about 200 μm in diameter,
from the respiratory bronchioles, alveolar ducts, and alveolar sacs
- are responsible for the spongy structure of the lungs
- Each adult lung has approximately 200 million __
with a total internal surface area of 75 m2.
- Air in these structures exchanges O2 and CO2 with the blood in surrounding capillaries, through thin specialized alveolar walls that enhance diffusion between the external and internal environments.
Alveoli
183
- Between neighboring alveoli lie thin __ consisting of scattered fibroblasts and sparse extracellular matrix (ECM), notably elastic and reticular fibers, of connective tissue.
- The arrangement of elastic fibers enables alveoli to
expand with inspiration and contract passively with expiration; reticular fibers prevent both collapse and excessive distention of alveoli.
- are vascularized with the richest capillary networks in the body
interalveolar septa
184
The densely anastomosing pulmonary capillaries within
the interalveolar septa are supported by the meshwork of reticular and elastic fibers, which also provide the primary structural support of the alveoli. Air in the alveoli is separated from capillary blood by three components referred to collectively as the respiratory membrane or __
blood-air barrier
185
3 Components of Blood-Air Barrier
■ two to three highly attenuated, thin cells lining the
alveolus,
■ the fused basal laminae of these cells and of the capillary
endothelial cells, and
■ the thin endothelial cells of the capillary.
186
- ranging 10-15 μm in diameter, penetrate the interalveolar
septa and connect neighboring alveoli that open to different bronchioles.
- The pores equalize air pressure in these alveoli and permit collateral circulation of air when a bronchiole is obstructed.
Alveolar pores (of Kohn)
187
- are extremely thin but continuous and not fenestrated. Clustering of most organelles around the nucleus allows the remaining areas ofthe cell to become very thin and demonstrate highly efficient gas exchange.
- the most prominent features in the flattened portions of the cell are numerous pinocytotic vesicles.
Capillary endothelial cells
188
- are also extremely attenuated cells that line the alveolar surfaces.
- maintain the alveolar side of the blood-air barrier and
cover about 95% of the alveolar surface
- These cells are so thin that the TEM was needed to prove that all alveoli have an epithelial lining
- Organelles are grouped around the nucleus, reducing the thickness of the cytoplasm at the blood-air barrier to as little as 25 nm.
- epithelial cells have occluding junctions that prevent the leakage of tissue fluid into the alveolar air space
Type I alveolar cells (or type I pneumocytes)
189
- are cuboidal cells that bulge into the air space
- often occur in groups of two or three along at points where two or more alveolar walls unite.
- contain lamellar bodies which contains surfactant
- divide to replace their own population after injury and to provide progenitor cells for the type I cell population.
- nuclei are rounded and may have nucleoli, and their cytoplasm is typically lightly stained with many vesicles.
Type II alveolar cells (type II pneumocytes or septal cells)
190
The __ film lowers surface tension at the air-epithelium interface, which helps prevent alveolar collapse at exhalation and allows alveoli to be inflated with less inspiratory force, easing the work of breathing.
surfactant
191
Critical components of the surfactant layer produced by type II alveolar cells include the phospholipid __, cholesterol, and four surfactant proteins.
dipalmitoylphosphatidylcholine (DPPC)
192
a very abundant hydrophilic glycoprotein
Surfactant protein A (SP-A)
193
are important for innate immune protection within the lungs.
Surfactant protein D
194
are required for the maturation of DPPC and its proper orientation in the surfactant film inside the alveolus.
Surfactant Protein-B and Surfactant Protein-C
195
In fetal development, surfactant appears in the last weeks of gestation as type II cells differentiate and Alveolar walls form lamellar bodies. Lack of adequate surfactant is a major
cause of __ in premature neonates.
respiratory distress
196
- also called dust cells, are found in alveoli and in the interalveolar septum
- Tens of millions of monocytes migrate daily from the
microvasculature into the lung tissue, where they phagocytose erythrocytes lost from damaged capillaries and airborne particulate matter that has penetrated as far as the alveoli.
Alveolar macrophages
197
- As the secretions pass up through the airways, they combine with bronchial mucus to form __, which helps remove particulate components from inspired air.
- It is bacteriostatic, containing lysozyme and other protective agents produced by Clara cells, type II alveolar cells, and alveolar macrophages
bronchoalveolar fluid
198
The lung’s outer surface and the internal wall of the thoracic cavity are covered by a serous membrane called the __
pleura
199
The membrane attached to lung tissue is called the visceral pleura and the membrane lining the thoracic walls is the __.
parietal pleura
200
The narrow __ between the parietal and visceral layers is entirely lined with mesothelial cells that normally produce a thin film of serous fluid that acts as a lubricant, facilitating the smooth sliding of one surface over the other during respiratory movements.
pleural cavity
Histology
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