Lab 4

Question 1

layers of blood vessels

Answer 1

• Tunica Intima (innermost)
• Tunica Media
• Tunica Adventitia

Question 2

describe Tunica Intima

Answer 2

• endothelium,
• a single layer of flattened cells
• supported by a basement membrane and subendothelial layer of connective tissue -> not visible in staining
• called the endocardium in the heart

Question 3

describe Tunica Media

Answer 3

• thick smooth muscle arranged circumferentially
• relatively thick in arteries
• contraction of smooth muscle causes vasoconstriction
• in the heart, the middle layer is made of cardiac muscle, not smooth

Question 4

describe Tunica Adventitia

Answer 4

• outer layer
• connective tissue
• mostly collagen and a few elastic fibres
• relatively thin in arterial system
• thick in venules and veins
• outer layer of heart is called epicardium, heart itself sits inside pericardium

Question 5

explain sturcture of capillaries

Answer 5

• single layer of flattened endothelial cells with a basal lamina underneath
• basal lamina
• no adventrial layer
• will have singular red blood cell in the lumen (erythrocyte)

Question 6

explain an elastic artery

Answer 6

• arteries, aorta carotid arteries
• tunica media is very thick and elastic fibres
• includes the Aorta
• tunica adventitia is mostly fibrous connective tissue

Question 7

exaplin a muscular artery

Answer 7

• tunica media mostly smooth muscle with few elastic fibres scattered
• prominent internal elastic lamina -> outermost part of the tunica intima
• wide layer of tunica media -> multiple layers of smooth muscle (less elastin)

Question 8

explain an arteriole

Answer 8

• tunica media almost entirely smooth muscle
• plump endothelial cell nuclei

Question 9

explain structure of a vein

Answer 9

• larger lumen
• tunica intima mainly thin endothelial cell lining
• tunica media is thinner than arteries
• tunica adventitia is the thickest layer, composed of collagen and elastin fibres which blend with the surrounding connective tissue
• often blood-filled lumen
• flat endothelia
• valves

Question 10

what are valves made of

Answer 10

• projections of the tunica intima from the vessel wall
• fibrous connective tissue lined by endothelium

Question 11

order of respiratory tubes

Answer 11

trachea -> bronchi -> bronchioles -> terminal bronchioles -> respiratory bronchioles (only in some species) -> alveolar ducts -> alveoli (alveolar sacs)

Question 12

usual structure of respiratory layers

Answer 12

1. mucosa -> epithelium and lamina propria
2. smooth muscle in bronchi and bronchioles (not trachea or alveoli)
3. submucosa

Question 13

structure of trachea

Answer 13

• submucosa contains serous and mucous glands -> cartilage externally
• pseudostratified, columnar, ciliated epithelium
• numerous goblet cells
• no smooth muscle
• ducts include seromucous gland ducts

Question 14

bronchioles

Answer 14

• epithelium is columnar/oval,
• cilia are rare
• few goblet cells within epithelia
• smooth muscle under mucosa layers
• no cartilage
• mucosa
• submucosa (smooth muscle)

Question 15

bronchi

Answer 15

• smooth muscle under mucosa layers
• submucosa contains serous and mucous glands
• pseudostratified, columnar, ciliated epithelium
• cartilage
• goblet cells and seromucous glands numerous
• lamina propria = fibrous connective tissue beneath epithelium, contains lymphocytes -> bronchiolar-associated lymphoid tissue (BALT)
• Both bronchi and bronchioles have smooth muscle between the mucosa and submucosa, which can contract and alter airway diameter.

Question 16

different types of bronchioles

Answer 16

• Terminal bronchioles have cuboidal rather than columnar epithelium, goblet cells are absent and cilia are rare. ->
• Respiratory bronchioles have cuboidal, non-ciliated epithelium

Question 17

Alveoli

Answer 17

• wall consists of flattened epithelium and an underlying layer of connective tissue for support
  wthin the connective tissue, many capillaries exist for exchange
• absent cilia in all alveolar structures
• no goblet cells
• walls are flattened, pseudostratified, columnar epithelium,

Question 18

types of cells in alveoli

Answer 18

1. Type 1 Pneumocytes
   - extremely thin, squamous cells – most common and abundant
   - deeply basophilic nuclei, thin, squamous
   - superficial/apical nuclei, very flattened, not plump
2. Type 2 Pneumocytes
   - cuboidal cells, plump
   - cover only 5% alveolar surface
3. alveolar macrophages
   - found in walls and sometimes in air space
   - central, deeply basophilic nucleus, large

Question 19

lung tissues

Answer 19

Pleura:
- thin, flattened epithelium
- visceral and parietal pleura – visceral on lungs, parietal lines thoracic wall
- separated by space containing small amount of serous fluid