Circulatory system

Question 1

Tunica intima

Answer 1

INNER
Endothelium (epithelial cells)
Reduce friction

Question 2

Tunica media

Answer 2

MIDDLE
Muscle cells
Alter vessel diameter

Question 3

Tunica externa

Answer 3

OUTER
Connective tissue
Protection and anchor to surrounding tissue

Question 4

Arteries

Answer 4

Carry blood AWAY from the heart

Question 5

Elastic arteries

Answer 5

Conducting vessel

High elastin content

Question 6

Muscular arteries

Answer 6

Distributing vessels
Thick tunica media
Change diameter to control blood flow

Question 7

Arterioles

Answer 7

Resistance vessels
Thin walls, mainly TM
Control resistance to blood flow and flow into capillaries

Question 8

Capillaires

Answer 8

Connect arteries and veins

EXCHANGE VESSELS - site of nutrient exchange

Question 9

Continuous capillaries

Answer 9

Endothelial cells
Gaps in endothelial cells = intercellular clefts
Fluid and sml solutes enter via IC clefts

Question 10

Fenestrated capillaries

Answer 10

Endothelial cells
Pores = fenestrations increase permeability
Larger volumes of fluid and solutes can enter/exit

Question 11

Sinusoidal capillaries

Answer 11

Endothelial cells
Large gaps = sinusoids = leaky
Larges molecules to pass through

Question 12

Terminal arteriole

Answer 12

Supplies capillary bed with O2 blood

Question 13

Terminal venule

Answer 13

Drains deO2 blood from capillary bed

Question 14

Veins

Answer 14

CAPACITANCE VESSLES
Tunica intima forms valves
Thick tunica externa
60% blood volume reservoir in veins

Question 15

Blood flow

Answer 15

The VOLUME of blood flowing through a vessel organ or the entire circulation in a given time period

Question 16

Blood pressure

Answer 16

The FORCE exerted on a vessel wall by the blood in that vessel

Question 17

Resistance

Answer 17

Opposition to blood flow

Friction

Question 18

BF =

Answer 18

P/R

Question 19

PP =

Answer 19

Difference between systolic and diastolic pressure

S - D

Question 20

MAP =

Answer 20

D + 1/3(PP)

Question 21

In which vessel does the biggest drop in BP occur

Answer 21

Capillaries
High P can damage thin walls
Permeable, so low P required for fluid exchange

Question 22

How do veins provide adequate venous return

Answer 22

Valves
Muscle pump
Respiratory pump
Pulsation 
Venoconstriction

Question 23

Functions of autoregulation of BP

Answer 23

Metabolic control

Myogenetic (muscle) control

Question 24

Functions of neural regulation of BP

Answer 24

Cardioinhibitory: parasymp to SA and AV nodes to dec HR and CO

Cardioacceletory: symp to SA and AV nodes to inc HR and CO AND symp to ventricular myocardium to inc force (SV) and CO

Vasomotor: symp to change vessel diameter **Baroreceptor reflex

Question 25

Functions of renal mechansms

Answer 25

Direct mechanism: rate of urine formation

Indirect mechanism: RAAS

Question 26

RAAS

Answer 26

Dec Art P
Inhibits baroreceptors
Inc RENIN release. Stimulates:
- Angiotensinogen 
- Angiotensin I (ACE)
- ANGIOTENSIN II:

1. Stims inc aldosterone release to inc Na+ (and water) reabsorption
2. Inc ADH release == inc water reabsorption
3. Inc thirst == inc water intake
4. Vasocontriction == inc peripheral resistance

==> Inc MAP

Question 27

Baroreceptor reflex for inc BP

Answer 27

Barorecs stimulates
Inc parasymp and dec symp to heart = dec HR, SV and CO
Dec symp to tunica media = vasodilation = dec R
=> Dec CO and R == dec BP to homeostatic range

Question 28

Baroreceptor reflex for dec BP

Answer 28

Barorecs inhibited
Dec parasymp and inc symp to heart = inc HR, SV and CO
Inc symp to tunica media = vasoconstriction = inc R
=> Inc CO and R == inc BP to homeostatic range

Question 29

Hormones that inc BP

Answer 29

A
NA
Angiotensin II

Question 30

Hormones that dec BP

Answer 30

Atrial natriuetic peptide (ANP)