Exam 2

Question 1

Describe the functions of the lymphatic system

Answer 1

a. Lymph vessels transport dietary lipids
i. Lymphatic capillaries called lacteals absorb lipids in intestine
b. Lymphatic organs aid in the production and maturation of lymphocytes
c. Lymphatic system generates immune response against antigens
i. Lymphocytes and macrophages monitor body for foreign substances
1. Some of the cells produce antibody proteins that bind the pathogen
2. Other lymphatic cells attach the antigen directly
3. Other lymphatic cells become memory cells to quickly attack the antigen if it appears again
d. Provides the space for lymph fluid to flow
e. Lymph vessel network transports excess fluid back to the blood

Question 2

Identify the organs of the lymphatic system, and the general functions of each organ, including lymph nodes, tonsils, spleen, thymus.

Answer 2

Lymph nodes: filter antigens from lymph and initiate an immune response

Tonsils: immune surveillance of inhaled and ingested substances

Spleen: initiates an immune response when antigens are found in blood, serves as a reservoir for erythrocytes and platelets, phagocytizes old, defective erythrocytes and platelets and bacteria/other foreign materials

Thymus: site of T-lymphocytes differentiation and maturation

Question 3

Describe the pathway of the lymphatic system from the capillary level to return of fluid to the venous system. Indicate the importance of the thoracic duct and the right lymphatic duct.

Answer 3

As it flows through the network, lymph is carried through progressively larger diameter vessels:
Lymphatic capillaries – lymphatic vessels – lymphatic trunks – lymphatic ducts
Afferent lymphatic vessels bring lymph to a lymph node
Efferent lymphatic vessels transport filtered lymph away from the lymph node

The right lymphatic duct returns lymph from the right side of the head and neck, right upper limb and right side of the thorax.
The thoracic duct collects lymph from most of the body (excluding right lymphatic duct drainage)

Question 4

Explain how lymphatic vessels help maintain interstitial fluid balance.

Answer 4

Hydrostatic pressure: physical pressure of blood flowing through the vessels or of fluid in interstitial spaces; force exerted by the fluid pressing against a wall.
Osmotic pressure: movement of solutes (plasma or tissue fluid) through the plasma membrane in the presence of large proteins
The difference in protein concentrations between the blood and interstitial fluid is responsible for osmosis
i. Anchoring filaments linking endothelial cells to surrounding structures prevent vessel collapse
ii. Pressure of lymph inside vessel forces intercellular openings (“flaps”) of capillary wall to close with lymph inside
b. Lymph moves through vessels of larger and larger size
c. Net filtration pressure (NFP)
NFP = Net hydrostatic pressure (NHP) minus net osmotic pressure (NCOP)
i. Arterial end of capillary
1. Net hydrostatic pressure > Net colloid osmotic pressure
a. Net pressure out
b. Filtration
ii. Venous end of capillary
1. Net colloid osmotic pressure (COP) > net hydrostatic pressure (HP)
a. Net pressure in
b. Reabsorption

Question 5

Describe the various infectious agents that impact the human body

Answer 5

a. Viral: Pieces of DNA or RNA in protein shell, Not cells- much smaller
Obligate intracellular parasites: Must enter cell to reproduce, Direct infected cell to make copies of nucleic acid and capsid, Virus or immune response may kill host cell
b. Bacterial: Single celled prokaryotes: Small cell with both a membrane and cell wall, Can be harmless or virulent
c. Fungal: Eukaryotic cells with membrane and cell wall
d. Prions: Fragments of infectious proteins, Neither cells nor viruses, Cause disease in nervous tissue
e. Protozoans: Eukaryotic cells without cell wall, Intracellular and extracellular parasites
f. Multicellular parasites: Non-microscopic, Take nourishment from host they live in

Question 6

identify the specific white blood cells involved in immune function

Answer 6

Neutrophils (most abundant leukocytes): phagocytize pathogens
Eosinophils: phagocytize antigen-antibody complexes, release chemical mediators to destroy parasitic worms
Basophils: release histamine causing vasodilation
Lymphocytes: coordinate immune cell activity, attack pathogens and abnormal and infected cells, produce antibodies (active immunity)
Monocytes: become macrophages

Question 7

Compare innate immune responses to adaptive immune responses

Answer 7

Innate
- provides fast general defense
- recognize some general molecular property marking the invader as foreign and protect the body as the first line of defense
- responds nonspecifically to range of harmful substances
- most immune cells: macrophages, NK cells
- chemicals: interferon, complement
- physiological responses: inflammation, fever
- cell mediated
- toll-like receptors
- complement system
- opsonization
- proinflammatory chemical secreting cells
- basophils, mast cells which promote inflammation
- phagocytes: neutrophils, macrophages, dendritic cells
- humoral: interferons, complement proteins, opsonins
- first line defense is skin, mucosal membrane and secretion
- second line of defense involves internal processes

Adaptive
- provided by lymphocytes that are activated to replicate and respond when stimulated by specific antigen
- there is a diversity of lymphocytes and receptors
- there is self-tolerance; lack of reactivity against an animals’ own molecules
- B and T cells proliferate after activation
- Immunological memory
- T lymphocytes: cell-mediated
- B lymphocytes: humoral (antibody production)
- specific responsive elements to certain pathogens
- differentiated cells: effector and memory

Question 8

Distinguish how toll-like receptors, interferon and complement proteins function in immune protection.

Answer 8

1. Toll like receptors: play critical roles as pattern recognition receptors, mainly expressed in antigen presenting cells (macrophages/dendritic), signaling activates antigen presenting cells to provoke innate immune response and to establish adaptive immunity.
2. Complement system: kills pathogens and triggers immune response. Composed of family of plasma proteins that lyse foreign cells, especially bacteria. Involves membrane attack complex which causes perforation in cells it attacks.
3. interferon: transiently inhibits multiplication of viruses in most cells, released from virus-infected cells, acts as “whistle-blower”

Question 9

Contrast active acquired immunity to passive acquired immunity

Answer 9

1. Active: antibodies developed in response to infection or developed in response to vaccination. Resistance built up as a result of body’s contact with microbes and their toxins or other antigenic components
2. Passive: antibodies received from mother or from medicine. Direct transfer of antibodies from one person to another, recipient receives pre-formed antibodies

Question 10

Explain the various types of acquired immune cells, where they are formed and their physiological roles in immunity: T, B, and Helper T.

Answer 10

1. T cells: formed in bone marrow, mature in thymus
   - Cytotoxic: recognize antigen-MHC1 on infected cells
   - mediates cell-mediated adaptive immunity
2. B cells: formed in bone marrow, mature in bone marrow
   - have antibody plasma proteins and antigen binding sites
3. Helper T: recognize antigen-MHC2 on antigen presenting cell

Question 11

Describe the five different types of antibodies, and generally how they work

Answer 11

1. IgA: class of antibodies secreted by cells lining the GI, respiratory, and genitourinary tracts. Accounts for 10-15% of antibodies.
2. IgD: A class of antibodies whose function is unknown
3. IgE: the class of antibodies that mediates immediate hypersensitivity to pollen, spores, animal dander. four in lungs, skin, mucus membranes
4. IgG: the most abundant class of plasma antibodies (75%): found in all body fluids. target viruses and bacteria. only antibodies that can cross the placenta.
5. IgM: i. Largest class of antibodies, 5-10%. Found in blood and lymph fluid. Produced first in all immune responses. Along with IgG, provide the bulk of specific humoral immunity against bacteria and viruses.

Question 12

Identify the physiological factors that can alter the body’s immune system

Answer 12

1. Age: size of thymus changes (shrinks with age)
2. protein-calorie malnutrition
3. preexisting disease
4. most exercise and physical conditioning
5. stress and person’s state of mind
6. sleep deprivation

Question 13

Describe the structural anatomy of the respiratory system

Answer 13

1. Conducting division: passages for air flow (without gas exchange); nose, pharynx, larynx, trachea, bronchus, bronchiole, terminal bronchioles
2. Respiratory division: gas exchange areas; respiratory bronchioles and alveoli

Question 14

Differentiate between the upper and lower respiratory tracts

Answer 14

1. Upper: nose, pharynx, larynx
2. Lower: trachea, bronchi, lungs, branches within lungs

Question 15

Compare and contrast external and internal respiration

Answer 15

Internal respiration: at the level of the tissues
External respiration: at the lungs

Question 16

Explain the anatomy and functions of the nasal cavity.

Answer 16

Anatomy:
- hard palate: floor of nasal cavity
- nasal septum: divides cavity. Anterior cartilage; posterior vomer and perpendicular plate of ethmoid
- nasal conchae
Functions
- passageway for air
- cleans, humidifies, warms air
-smell
- along with paranasal sinuses, are responding chambers for speech

Question 17

Explain the anatomy and functions of the pharynx

Answer 17

1. Nasopharynx
   - pseudostratified columnar epithelium with goblet cells
   - openings of eustachian (auditory) tubes
   - floor is soft palate, uvula is posterior extension of the soft palate
2. Oropharynx
   - shared with digestive system
   - lined with moist stratified squamous epithelium
3. Laryngopharynx
   - epiglottis to esophagus
   - lined with moist stratified squamous epithelium
   Function:
   Serves as common opening for respiratory and digestive systems

Question 18

Explain the anatomy and functions of the larynx

Answer 18

1. Large cartilaginous structure in throat
   - thyroid: largest, “adam’s apple”
   - cricoid: most inferior, base of larynx
   - epiglottis: attached to the thyroid and has a flap near base of tongue, elastic rather than hyaline cartilage
2. paired
   - vestibular folds or false vocal folds
   - true vocal cords or vocal folds: sound production
3. glottis
   - opening between folds

Question 19

Describe the cellular organization of the trachea and its importance

Answer 19

a. Membranous tube of dense regular connective tissue and smooth muscle
b. Inner lining: pseudostratified ciliated columnar epithelium with goblet cells
i. Mucus traps debris cilia push it superiorly toward larynx and pharynx

Question 20

Identify how the trachea branches as it descends into the lungs

Answer 20

a. Trachea divides into two primary bronchi
b. Primary bronchi divide into secondary bronchi, then divide into tertiary bronchi
c. Tertiary bronchi further subdivide into bronchioles then finally into terminal bronchioles.

Question 21

Define the respiratory zone of the lungs

Answer 21

a. This is composed of the respiratory bronchiole, alveolar duct, alveoli
b. Site for gas exchange
c. Respiratory bronchioles branch from terminal bronchioles
d. Respiratory bronchioles have very few alveoli
e. Alveolar sacs have multiple alveoli at their terminus
f. No cilia, but debris removed by macrophages

Question 22

Explain the functional organization of the lungs: lobes and fissures

Answer 22

a. Base sits on the diaphragm, apex at the top, hilum on medial surface where bronchi and blood vessels enter the lung
b. Right lung: three lobes. Lobes separated by fissures.
c. Left lung: two lobes, and an indentation called the cardiac notch

Question 23

Describe the respiratory membrane structures and the cell types that are responsible for respiration

Answer 23

• thin layer of fluid lining the alveolus (surfactant)
• alveolar epithelium (simple squamous epithelium)
• basement membrane of alveolar epithelium
• basement membrane of capillary endothelium
• capillary endothelium composed of simple squamous epithelium
  Cell types
• Type 1 pneumocytes. thin squamous epithelial cells, form 90% of surface of alveolus. gas exchange
• Type 2 pneumocytes. surfactant producers
• macrophage cells: immune cells in alveoli

Question 24

Identify the function of the pleura

Answer 24

Allows for lung inflation by having intrapleural pressure lower than intrapulmonary pressure and lung deflation when intrapleural pressure is higher than intrapulmonary pressure

Question 25

Compare and contrast the muscles of inspiration and expiration

Answer 25

a. Muscles of inspiration Diaphragm (passive) External intercostals (active) Pectoralis minor (accessory) Sternocleidomastoid (acc) b. Muscles of expiration Diaphragm (relaxing) Internal intercostals (active) Abdominals (accessory, active)

Question 26

Indicate the pathway of blood flow to/from the alveoli for gas exchange, and the pathway of blood flow to supply lung tissue

Answer 26

a. To the alveoli i. From the right side of the heart ii. Through the vena cava to the right atrium to the right ventricle through the pulmonary trunk into the pulmonary arteries into arterioles into pulmonary capillaries into alveoli iii. These enter into the venules and then into pulmonary veins into the left atrium into the left ventricle and into the aorta b. Supplying lung tissue i. Bronchial arteries follow branching of bronchial tree to terminal bronchioles. Bring oxygenated blood to the tissues of the bronchi

Question 27

Explain the neural control of inspiration/expiration

Answer 27

a. Respiratory center in the medulla oblongata controls the rate and depth of breathing b. The ventral respiratory group (VRG) controls inhalation and exhalation via phrenic and intercostal nerves to the diaphragm and intercostal muscles respectively. c. The dorsal respiratory group (DRG) receives information from sensory receptors in the body and relays its input to the VRG.

Question 28

Define ventilation

Answer 28

The exchange of air between the atmosphere and alveoli

Question 29

Explain the steps of respiration (both inspiration and expiration)

Answer 29

a. Inspiration i. Diaphragm and external intercostals contract ii. Thorax expands iii. Pip becomes more sub atmospheric 1. Interpleural pressure is below 760 mmHg iv. Transpulmonary pressure increases v. Lungs expand vi. Palv becomes sub atmospheric vii. Air flows into the alveoli b. Expiration i. Diaphragm and internal intercostals stop contracting ii. Chest wall recoils inward iii. Pip moves back towards preinspiration value iv. Transpulmonary pressure moves back toward preinspiration value v. Lungs recoil toward preinspiration size vi. Air in alveoli becomes compressed vii. Palv becomes greater than Patm viii. Air flows out of the lungs

Question 30

Identify the partial pressure of gases in atmospheric air, in the alveoli, and in the body tissues

Answer 30

a. PO2 i. 760mmHg in atmospheric air ii. 100mmHg in alveoli iii. 40mmHg in capillaries b. PCO2 i. 40mmHg in alveoli ii. 45 mmHg in capillaries

Question 31

Explain how gas exchange occurs at the alveoli and the body tissues by the process of diffusion.

Answer 31

Gas molecules want to move from an area of higher pressure to an area of lower pressure

Question 32

Describe the Oxygen-Hemoglobin Dissociation Curve and its importance.

Answer 32

a. As the partial pressure of oxygen increases, the percent O2 saturation of hemoglobin increases b. This has important implications for body temp, pH and altitude.

Question 33

Explain the factors involved in the normal breathing cycle and the different changes that occur during inspiration vs expiration.

Answer 33

a. Physiology of quiet breathing i. Inspiration begins with VRG inspiratory neurons fire spontaneously ii. Signals are sent from VRG to nerve pathways exciting skeletal muscle for about 2 sec iii. Quiet expiration occurs when VRG is inhibited iv. Signals are no longer sent to the muscles (for about 3 sec) v. Respiratory rate for normal, quiet breathing is eupnea 1. 12-16 breaths/min vi. Pontine respiratory center facilitates smooth transitions between inspiration and expiration b. Physiology of forced breathing i. Involves steps similar to quiet breathing ii. Requires contraction of additional muscles iii. Causes greater changes in thoracic cavity volume and intrapulmonary pressure iv. More air moves into and out of lungs v. Significant chest volume changes are apparent

Question 34

Define flow and the relationship of air flow (or blood flow) to pressure and resistance: F = P1-P2/R

Answer 34

a. Flow is the change in pressure over resistance b. Flow and resistance are inversely related c. Flow and pressure are directly related

Question 35

Define pressure gradient

Answer 35

i. Difference between atmospheric pressure and intrapulmonary pressure 1. Can be change by altering volume of thoracic cavity

Question 36

In terms of air flow, define resistance

Answer 36

i. Factors that increase difficulty moving air 1. Change in elasticity of chest wall and lungs 2. Change in bronchiole diameter (size of air passageway) 3. Collapse of alveoli

Question 37

In terms of air flow, define compliance

Answer 37

i. The magnitude of the change in lung volume produced by a given change in the transpulmonary pressure ii. Factors that influence lung compliance 1. Elastic property of lung tissue 2. Surface tension elastic force 3. Surfactant 4. Lung volume 5. Age

Question 38

Identify neural control of pons, medulla, cerebellum, cerebral cortex; and phrenic, vagus, and intercostal nerves

Answer 38

a. Autonomic nuclei within the brain coordinate breathing i. Respiratory center of the brainstem 1. Medullary respiratory center a. Generate the respiratory rhythm b. Output from the medullary respiratory centers descends in the reticulospinal tract in the anterolateral funiculus of the spinal cord c. Ventral respiratory group (VRG) in anterior medulla i. Both inspiratory and expiratory neurons ii. Responsible for the generation of the respiratory rhythm d. Cerebellum i. Fastigial nucleus produces early termination of the bursting of both the inspiratory and expiratory neurons e. Dorsal respiratory group (DRG) in poster medulla i. Mainly inspiratory (diaphragm control) ii. Receive pulmonary afferent input from the vagus nerve iii. Appear to serve as primary rhythmic drive to phrenic motor neurons iv. Modulated by GABA receptors 2. Pontine respiratory group (PRG) in pons aka pneumotaxic center a. Involved in modification and fine control of the respiratory rhythm b. The PRG contains inspiratory, expiratory, and phase-spanning neurons c. Receives vagal afferents relating to lung volume, modulates respiratory frequency d. Primary connections are with medullary respiratory neurons; also has connections with the hypothalamus, cerebral cortex, and the nucleus of the tractus solitarius e. Not essential for respiratory rhythm generation b. Brainstem neurons influence respiratory muscles i. VRG neurons synapse with lower motor neurons of skeletal muscles in spinal cord ii. Lower motor neuron axons project to respiratory muscles 1. Axons innervating diaphragm travel in phrenic nerves 2. Axons innervating intercostal muscles travel in intercostal nerves

Question 39

Explain how ventilation is regulated via physical, neural, and chemical control.

Answer 39

a. Normally the most important stimulus affecting breathing rate and depth is blood PCO2 b. Hypoxic drive – PO2 levels become stimulus for breathing i. Occurs in some respiratory disorders ii. CO2 levels in blood remain elevated for long period iii. Chemoreceptors become less sensitive to PCO2 iv. By default, decreased PO2 stimulates them v. Administering O2 can elevate PO2 and interfere with the person’s ability to breathe on their own

Question 40

Define the Hering-Brauer Reflex.

Answer 40

- Stretch receptors limit the degree of inspiration and prevents over-inflation of the lungs - Infants o Reflex plays a role in regulating basic rhythm of breathing and preventing over inflation of the lungs - Adults o Reflex important only when tidal volume is large as in exercise

Question 41

Describe the functions of the Urinary System.

Answer 41

a. Filtering the blood which involves three processes: filtration, reabsorption, secretion b. Regulation of i. Blood volume ii. Concentration of blood solutes: Na+, Cl-, Ca2+, HPO4 2- iii. pH of extracellular fluid: secrete H+ iv. Blood cell synthesis c. Production of hormones/enzymes i. Erythropoietin 1. Controls erythrocyte production ii. Renin 1. Enzyme that controls the formation of angiotensin, which influences blood pressure and sodium balance iii. Synthesis of vitamin D

Question 42

Identify the organs of the Urinary System and how they work together.

Answer 42

a. Kidney i. Filters blood b. Ureters i. Carries urine to urinary bladder from kidney c. Urinary bladder i. Pushes urine out of body via urethra d. Urethra

Question 43

Describe the structural/anatomical organization of a kidney and its structural and functional unit, the nephron.

Answer 43

a. Cortex: outer area b. Medulla: inner area; surrounds renal sinus c. Calyces i. Minor: papillae extend into funnel of minor calyx ii. Major: converge to form pelvis d. Pelvis: enlarged chamber formed by major calyces e. Ureter: exits at the hilum; connects to urinary bladder f. Nephron i. Bowman’s capsule ii. Proximal tubule iii. Loop of henle iv. Distal tubule v. Collecting duct

Question 44

Discuss the location and purpose of the major vascular structures of the nephron including the afferent and efferent arterioles, and the vasa recta.

Answer 44

a. Afferent arteriole i. Supplies blood to the glomerulus b. Efferent arteriole i. Drains glomerulus c. Vasa recta i. “Straight vessels” associated with the nephron loop ii. Primarily reside in the medulla of the kidney iii. Tubular reabsorption

Question 45

Describe the cellular structure and function of each region of the nephron.

Answer 45

a. Renal corpuscle i. Glomerulus 1. Network of capillaries ii. Bowman’s capsule 1. Outer parietal (simple squamous epithelium) and visceral (podocyte cells) layers. b. Renal tubule i. Proximal tubule 1. Convoluted tubule 2. Straight tubule ii. Loop of henle 1. Descending limb 2. Thin segment of ascending limb 3. Thick segment of ascending limb iii. Distal convoluted tubule iv. Collecting duct system 1. Cortical collecting duct 2. Medullary collecting duct

Question 46

Discuss the tissues features of the ureters

Answer 46

i. Three layered wall 1. Mucosa has transitional epithelium 2. Muscularis has multiple layers of smooth muscle 3. Adventitia is connective tissue binding to surrounding organs

Question 47

Discuss the tissues features of the bladder

Answer 47

i. Detrusor: muscular layer ii. Rugae: wrinkles of mucosa iii. Trigone: triangular region on floor of bladder defined by two ureter inlets and one urethra outlet

Question 48

Discuss the tissues features of the urethra

Answer 48

i. Two sphincters 1. Internal urethral sphincter 2. External urethral sphincter

Question 49

Discuss how filtration pressure is established, how it drives glomerular filtration, and how much cardiac output is filtered through the kidneys.

Answer 49

a. Pressure gradient responsible for filtration; forces fluid from glomerular capillary across membrane into lumen of Bowman’s capsules b. Requires higher pressure in capillaries of glomerulus that bowman’s capsule c. Filtration pressure = GCP-CHP-BCOP i. GCP: glomerular capillary pressure 1. Blood pressure inside the capillary tends to move fluid out of the capillary into Bowman’s capsule ii. CHP: capsular hydrostatic pressure 1. Pressure of filtrate already in the lumen iii. BCOP: blood colloid osmotic pressure 1. Favors fluid movement into capillary from the lumen 2. Osmotic pressure caused by proteins in blood

Question 50

Define: filtrate, renal fraction, filtration fraction, glomerular filtration rate (GFR)

Answer 50

a. Filtrate: water, small molecules, ions that can pass through membrane b. Renal fraction: part of total cardiac output that passes through the kidneys. Varies from 12-30%; averages 21% c. Filtration fraction: part of plasma that is filtered into lumen of bowman’s capsules: average 19% d. Glomerular filtration rate (GFR): amount of filtration produced each minute. 180 L/day (vs. 4 L/day by other systemic capillaries).

Question 51

Describe the process of urine production at the tubule level and explain how urine is concentrated

Answer 51

a. Filtration i. Filtration membrane acts as filtration barrier ii. Prevents blood cells and proteins from entering lumen of bowman’s capsule iii. Many times more permeable than a typical capillary iv. Some albumin and small hormonal proteins enter the filtrate v. Very little protein normally found in urine b. Tubular reabsorption i. Movement of substance from the fluid in the tubular lumen into the peritubular capillary ii. Occurs at loop of henle 1. Descending limb a. Interstitial fluid is high in solute b. Simple cuboidal epithelium c. Highly permeable to water leads to osmosis d. Water moves out of nephron 2. Ascending limb not permeable to water a. Na+ moves across wall of basal membrane by active transport c. Tubular secretion i. Distal tubule ii. Collecting ducts

Question 52

Explain countercurrent multiplication and the medullary concentration gradient and its importance in the urinary system.

Answer 52

a. Medullary vertical osmotic gradient is established by this b. Comparing the descending and ascending limbs of the loop of henle i. Descending limb is highly permeable to water but does not extrude sodium for reabsorption ii. Ascending limb actively transports NaCl out of tubular lumen into the surrounding interstitial fluid. It is impermeable to water. Thus, water does not follow the salt by osmosis iii. Thus… there is a countercurrent flow produced by the close proximity of the two limbs c. The ascending limb produces an interstitial fluid that becomes hypertonic to the descending limb

Question 53

Describe the urea cycle and how it’s involved in maintaining appropriate medullary Concentration.

Answer 53

a. Urea: enters glomerular filtrate i. As volume of filtrate decreases, concentration of urea increases ii. Walls of nephron not very permeable to urea: only 40-60% passively reabsorbed b. Urate ions, creatine, sulfates, phosphates, nitrates partially reabsorbed i. Concentration is high in urine ii. Toxic substances, thus are eliminated c. Responsible for large part of high osmolarity in medulla d. Descending limb of loops of Henle permeable to urea e. Ascending limbs and distal tubules impermeable to urea f. Collecting ducts permeable to urea g. Urea flows in a cycle maintains high urea concentration in medulla

Question 54

Discuss how pH balance is maintained across multiple body systems and the importance of maintaining an appropriate pH level in the body.

Answer 54

Bicarbonate and H+ ions play significant role in pH of urine and blood. Filtered bicarb must be reclaimed to ensure blood pH does not become too acidic.

Question 55

Describe where ADH is produced, where it acts, and how it helps regulate water balance and blood pressure.

Answer 55

a. In DCT and collecting ducts b. When present, it ensures water is reabsorbed so that concentrated urine is produced. c. Inhibits water elimination d. Inserts aquaporins into collecting duct membrane to decrease the volume of urine produced and when venous return is increased, volume in the right atrium increases

Question 56

Define plasma clearance, tubular load, and tubular maximum

Answer 56

Plasma clearance: measures the volume of plasma that can be completely cleared of a substance in a given period of time. Tubular load: total amount of substance that passes through filtration membrane into nephrons each minute Tubular maximum: maximum rate at which a substance can be actively absorbed

Question 57

Explain the effects of diuretics (enhanced urine production) on renal function

Answer 57

a. Increase the volume of urine excreted b. Osmotic diuretics are filtered but not reabsorbed, thus retaining water in the urine c. Loop diuretics act on the ascending limb of the loop of henle to inhibit the first step in Na+ reabsorption in the segment—cotransport of Na+ and Cl- by the NKCC across the apical membrane d. Potassium-sparing diuretics inhibit Na+ reabsorption in the cortical collecting duct without increasing K+ secretion there. Either block the action of aldosterone or block the epithelial NA+ channel.

Question 58

Define renal clearance and tubular maximum

Answer 58

a. Renal clearance i. The volume of plasma from which that substance is completely removed by the kidneys per unit time. ii. Cs= clearance of S iii. Us= urine concentration of S iv. V= urine volume per unit time v. P=plasma concentration of S vi. Cs=UsV/Ps vii. Inulin is a substance that is freely filtered by the kidney, but is not reabsorbed or secreted; thus the renal clearance equals the GFR b. Tubular maximum i. Maximum rate at which a substance can be actively absorbed ii. Each substance has its own tubular maximum

Question 59

Place in order the events that occur as filtrate/urine moves through the urinary structures

Answer 59

a. Hydrostatic pressure forces urine through nephron b. Peristalsis moves urine through ureters from region of renal pelvis to urinary bladder i. Occur from once every few seconds or once every 2-3 min c. Ureters enter bladder obliquely through trigone. Pressure in bladder compresses ureter and prevents backflow.

Question 60

Explain the influence of the nervous system input on urinary/function/control

Answer 60

i. Peristalsis moves urine through ureters from region of renal pelvis to urinary bladder 1. Parasympathetic: increase frequency 2. Sympathetic: decrease frequency

Question 61

Describe the micturition reflex and how it works

Answer 61

The expulsion of urine from the bladder is micturition. It is regulated by the autonomic nervous system. Sympathetic division stimulation inhibits micturition. Requires relaxation of the internal urethral sphincter which is stimulated by parasympathetic activation.

Question 62

Identify some effects of aging on the urinary system

Answer 62

a. Kidneys atrophy with age—become less efficient i. Reduced renal function means drugs are not cleared from the body as quickly b. Kidneys become less sensitive to antidiuretic hormone i. Water balance becomes precarious c. Bladder control becomes problematic i. Urine retention ii. Urinary incontinence d. Gradual decrease in size of kidneys, but only one-third of one kidney necessary for homeostasis e. Amount of blood flowing through gradually decreases f. Number of glomeruli decrease and ability to secrete and reabsorb decreases g. Ability to concentrate urine declines and kidney becomes less responsive to ADH and aldosterone h. Reduced ability to participate in vitamin D synthesis contributes to Ca2+ deficiency

Question 63

Tidal volume

Answer 63

amount of air inspired or expired during normal, quiet ventilation