Circ System Histo

Question 1

components of CV system

Answer 1

heart, BVs, blood

Question 2

fnctn of CV system

Answer 2

transport (nutrients and oxygen, waste products, hormones)

Question 3

chambers of the heart

Answer 3

• 2 artia: receiving chambers (walls thinner than vents)

- 2 ventricles: discharging chambers (L wall much thicker then R)

Question 4

L side

Answer 4

systemic circuit

LA receives oxygenated blood

Question 5

R side

Answer 5

pulmonary circuit

RA receives deoxygenated blood

Question 6

components of heart wall

Answer 6

1. cardiac m
2. fibrous skeleton of heart (4 fibrous rings surround valve orifices, 2 fibrous trigones connect fibrous rings, membraneous portion of IV and IA septa)
3. conducting system
4. coronary vasculature
5. serous membrane
6. endothelial cells with underlying CT

Question 7

what are the 4 fibrous rings made of

Answer 7

dense irregular CT

Question 8

layers of heart wall

Answer 8

1. epicardium: outer layer (visceral layer/serous pericardium)
2. myocardium: middle, mainly cardiac m and fibrous skeleton of heart
3. endocardium: inner, 3 components

Question 9

3 components of endocardium

Answer 9

1. endothelial cells: against blood, inner
2. subendothelial layer: CT and smooth m
3. subendocardial layer: deep, CT and intrinsic conduction system

Question 10

composition of valves

Answer 10

CT and overlying endocardium

Question 11

semilunar valves

Answer 11

• prevent backflow into ventricles
• aortic and pulmonary valves
• both have three cusps

Question 12

do vena cava, coronary sinus, and pulm veins have valves?

Answer 12

no

Question 13

layers of valves

Answer 13

1. spongiosa: LCT covered in endothelium, atrial or BV side, collagen and elastic fibers auricularis
2. fibrosa: core of value, fibrous extensions fron DICT of skeletal rings arterialis
3. ventricularis: DCT with layers of elastic convered in endothelium, ventricular side of valve

Question 14

intrinsic conduction system

Answer 14

• cardiac m can depolarize and contract w/o impulses from NS
• 2 types of conducting cells
• organized into nodes, resp for initiation and distribution of impulse

Question 15

2 types of conducting cells

Answer 15

1. nodal cardiac cells: in SA and AV, modified, both cardiac m cells, no intercalated discs
2. purkinje fibers: AV bundle, bundle brs and subendo brs, intercalated discs, myofibrils, positive for PAS staining

Question 16

what influences rate of contraction

Answer 16

sympathetic: increase
parasympathetic: decrease

Question 17

types of BVs

Answer 17

1. arteries: blood away from heart, oxygenated to systemic, deoxy into pulm circ
2. capillaries: smallest BV, role in exchange, endothelial cell and basal lamina
3. veins: blood toward heart, deoxy blood insystemic, oxy blood in pulm

Question 18

layers of walls of BVs

Answer 18

1. tunica interna: endothelium->basal lamina->subendothelial layer *internal elastic membrane in aa and some arterioles
2. tunica media: rings of smooth m cells, sheets of elastin *external elastic mem: aa
3. tunica externa/adventitia: vasa vasorum in larger vessels

Question 19

thickest layer in vv

Answer 19

tunica externa

Question 20

thickest layer in aa

Answer 20

tunica media

Question 21

4 types of aa

Answer 21

1. elastic/conducting (large): >10 mm, large amts of elastic fiber, for expand and recoil
2. muscular/distributing (med): 2-10mm, large amts of elastic fiber, SM, reg blood flow in body regions
3. small aa: 1-2 mm, as many as 8 layers SM in tunica media
4. arterioles: only 1-2 layers SM in tunica media

Question 22

3 types of capillaries

Answer 22

1. continuous: muscle, lunds, CNS, uninterrupted lining with tight jncnts, pinocytotic vesicles
2. fenestrated: endocrine glands, oval pores, pino vesicles
3. discontinuous (sinusoids): liver, spleen, bone marrow, large diameter, irregularly shaped

Question 23

2 types of vessels in cap network

Answer 23

1. true capillaries
2. AV shunts (finger tips and erectile tissue)
   * relaxed precap sphincter and contracted AV shunt=blood thru true caps
   * contracted precap sphincter and relaxed AV shunt = blood thru shunt

Question 24

4 types of vv

Answer 24

1. venule: smallest diameter, receive blood from caps, 1. postcap, 2. muscular venules
2. small vv: receive blood from musc venule
3. med vv: all three layers present
4. large vv: all three layers present

Question 25

do vv in limbs have valves?

Answer 25

yes