#31

Question 1

Tunica Intima

Answer 1

The inner layer that surrounds the blood as it flows through the body

Question 2

Tunica Media

Answer 2

The middle layer that contains elastic fibers that keeo blood flowing in one direction

Question 3

Tunica externa

Answer 3

outermost layer of a blood vessel

Question 4

Basement membrane

Answer 4

extracellular matrix surrounding blood vessels acting as structural scaffold, filtration barrier and signaling platform

Question 5

Which vessels lack a basement membrane?

Answer 5

Sinusoidal capillaries

Question 6

Which vessels lack a tunica media?

Answer 6

Capillaries

Question 7

Which vessels have the narrowest lumen?

Answer 7

Capillaries

Question 8

Where are the main sites in the systemic circulatory system where changes in vessel diameter used to affect blood flow to particular tissues?

Answer 8

Arterioles and sometimes small arteries

Question 9

Intrinsic regulation (autoregulation)

Answer 9

Regulation by factors occuring within the local environment of that vessel
can be indirect or direct
- intrinsic ability of an organ to maintain a relatively constant blood flow

Question 10

Extrinsic regulation

Answer 10

Regulation by mechanisms involving integrative organ systems (outside local environment)

Question 11

Where is intrinsic regulation within?

Answer 11

Local capillary bed

Question 12

Paracrine factors

Answer 12

Chemical messengers that remain within their local environment

Question 13

How do paracrine signals/factors get generated?

Answer 13

Generated in response to metabolic changes or in response to local immune system activation

Question 14

Myogenic Mechanism

Answer 14

Arteriolar smooth muscle responds directly to stretch. increased pressure causes vessel constriction, decreased causes dilation

Question 15

Metabolic Mechanism

Answer 15

accumulation of metabolic waste products and decreased oxygen cause vasodilation, increasing blood flow to meet demand

Question 16

Angiogenesis

Answer 16

Growth of new blood vessels from pre-existing ones

Question 17

What does extrinsic regulation involve?

Answer 17

signals originating from outside the local capillary bed

Question 18

Neural Extrinsic regulation

Answer 18

sympathetic postganglionic axon terminals release norepinephrine to cause vaso constriction

Question 19

Hormonal Extrinsic regulation

Answer 19

epinephrine and angiorensis II are released into the bloodstream to act on specific adrenergic receptors

Question 20

α1 receptors location

Answer 20

smooth muscle in most vascular beds

Question 21

β receptors

Answer 21

receprots in skeletal muscle vessels

Question 22

What do β receptors do?

Answer 22

elevate intracelular cAMP reducing smooth muscle contration [vasodilation]

Question 23

what do α1 receptors do?

Answer 23

elevate intracellular calcium, enhancing smooth muscle contraction [vasoconstriction]

Question 24

What are α1 receptors sensitive to?

Answer 24

norepinephrine (ANS/SNS activity)

Question 25

What are β receptors sensitive to?

Answer 25

epinephrine (hormonal release)

Question 26

Active hyperemia

Answer 26

acute physiological increase in localized blood flow to tissues driven by heightened metabolic demand