Circulation in Animals II

Question 1

What are the 3 layers of vein and artery walls? and what do they do?

Answer 1

Outside Layer: connective tissude that allows the vessel to stretch and recoil.
Middle Layer: smooth muscle and elastic fibers.
Endothelium Layer: layer of flattened cells, minimizes resistance to flow.

Question 2

What is the only layer that capillaries have?

Answer 2

endothelium, thus enhancing gas and nutrient exchange

Question 3

Arteries have thicker ___ and ____ layers than veins. Provides _______ to acoomodate blood being pumped rapidly.

Answer 3

middle
outer
strength

Question 4

The ___ walled veins convey blood back to the heart at low _____ and ______.

Answer 4

thin
velocity
pressure

Question 5

The ___ slow down the flow of blood because they have a larger ________. The slow rate and thin walls enhance exchange between ________. Blood speeds up when it exits and passes to ________>

Answer 5

capillaries
cross sectional area
blood and intestinal fluid
venules and veins

Question 6

Blood pressure is the ______ force of blood on vessel walls. It is much greater in ____ than in veins. Highest when heart contracts creating _______.

Answer 6

hydrostatic
arteries
systolic pressure

Question 7

Healthy blood pressure at systole and diastole is?

Answer 7

120 systole and 70 diastole (mm Hg)

Question 8

Contraction of smooth muscles in artery walls increase ______. And there fore increases ____ and decreases _____. Opposite when they relax. What else controls artery wall muscles?

Answer 8

peripheral resistance
blood pressure
blood flow

nerves, hormones etc

Question 9

What is located at the entrance of capillary beds and controls blood flow between arterioles and venules?

Answer 9

Precapillary sphincters (rings of smooth muscles)

Question 10

Transport across capillary walls occurs mainly by _____ due to ________.

Answer 10

bulk flow

fluid pressure

Question 11

Fluids and blood proteins that leak from capillaries into intestinal fluid are returned to blood via the ______. Once inside the sytstem, the fluid is called a _____. The system drains into ______.

Answer 11

Lymphatic System
Lymph
circulatory system

Question 12

Lymph vessels have valves that prevent _______. Along lymph vessels are organs called ______ that _____ the lymph and attack viruses and bacteria.

Answer 12

backflow
lymph nodes
filter

Question 13

Lymphatic system also transports ____ from digestive tract to _____.

Answer 13

fats

circulatory system

Question 14

Blood is connective tissue suspended in liquid matrix called ______ that takes up 55% of blood volume. Other 45% is ____.

Answer 14

plasma

cells and cell fragments