Lecture 1

Question 1

What are the fluid systems in the body?

Answer 1

1. Blood Vascular System
2. Lymphatic System
3. Cerebrospinal Fluid
4. Coelomic / Peritoneal Fluid
5. Interstitial Fluid

Question 2

Open systems?

Answer 2

• Where the heart pumps blood to the tissues in closed arteries, without a venous return
• The heart pumps blood into vessels that have open ends

Question 3

Closed systems?

Answer 3

• Where blood never leaves the vessels

- Blood flows through a continuous circuit of blood vessels

Question 4

What are the main functions of the blood system?

Answer 4

• The transportation of necessary materials to the cells for their metabolism and synthesis
• The removal of this metabolic waste from each cell to organs that excrete them

Oxygen and nutrients must be supplied to the cells and carbon dioxide and nitrogenous wastes removed. Blood vessels carry this out.

Question 5

What are blood vessels divided into?

Answer 5

Arteries, capillaries and veins

Question 6

Blood flow?

Answer 6

Aorta - arteries - arterioles - metarterioles - arterial capillaries - venous capillaries - venules - veins - Vena Cava - Right atrium - Tricuspid valve - Right ventricle - Pulmonary valve - Pulmonary arteries - Lungs (gets O2) - Pulmonary veins - Left atrium - Bicuspid valve - Left ventricle - Aortic valve

Question 7

What are the 3 layers that make up the walls of arteries and veins?

Answer 7

Tunica Intima, Tunica Media, and Tunica Adventitia/Externa

Question 8

What is Tunica Intima made from in veins vs. arteries?

Answer 8

Arteries:

• Endothelium
• Elastic fibres
• Collagen fibre

Veins:
- Endothelium

Question 9

What is Tunica Media made from in veins vs. arteries?

Answer 9

Arteries:

• Smooth muscle [except Aorta]
• Collagen fibres
• Elastic fibres (few) [Aorta sheets]

Veins:
- Smooth muscle - thin layers

Question 10

What is Tunica Adventitia/Externa made from in veins vs. arteries?

Answer 10

Arteries:

• Collagen fibres
• Elastic fibres (scattered)

Veins:
- Collagen fibres - thick; in layers

Question 11

Arteries?

Answer 11

• In large arteries (aorta) there is little muscle in the tunica media and it mostly consists of sheets of elastic tissue
• Medium sized arteries have lots of smooth muscle in the tunica media
• They also have a nerve supply from the sympathetic nervous system enabling the control of blood flow
• Take oxygenated blood away from the heart

Question 12

How do veins compare to arteries?

Answer 12

Veins are similar to arteries in structure but the walls are thinner and have less smooth muscle and elastic tissue

Arteries - Take oxygenated blood away from the heart
Veins - Take deoxygenated blood towards the heart

Question 13

What is interstitial fluid?

Answer 13

• Fluid between cells
• Provides a medium for diffusion of oxygen, nutrients and waste
• Where most cells obtain their nutrient and oxygen requirements from

Question 14

What is the function of the circulatory system?

Answer 14

• The time required for diffusion increases with the distance over which the diffusion occurs.
• Some cells, which are at a distance, wouldn’t survive if it depended on diffusion alone.
• So the evolution of circulatory systems allows animals to increase in size and become many cells thick, decreasing the distance that needed materials must diffuse
• It transports oxygen, nutrients, hormones and other materials to the interstitial fluid surrounding the cells, and removed metabolic waste

Question 15

What are the two main types of circulatory systems?

Answer 15

Open and closed

Question 16

What are capillaries?

Answer 16

• The tiniest blood vessel (one layer of endothelial cells)
• Grouped in beds in the body
• Have very thin walls that permit exchange of materials between blood and interstitial fluid
• Blood doesn’t continuously flow through the capillary beds, only a tiny number of capillaries are filled with blood

Question 17

Function of arteries?

Answer 17

• Carries blood away from the heart chamber toward other tissues

Question 18

When an artery enters an organ, what does it divide into?

Answer 18

Many smaller branches called arterioles

Question 19

What is the vasa vasorum?

Answer 19

The blood supply feeding into large arteries and veins

Question 20

What is the purpose of the valves in veins?

Answer 20

Prevent the back flow of blood away from the heart

Question 21

Preferential channels?

Answer 21

• Beside the capillary beds

- Shunt blood rapidly from the arterial to the venous side

Question 22

Does blood flow continuously through the capillary beds?

Answer 22

No, only a small number of capillaries are filled

Question 23

What is the intermittent blood flow in the capillary bed is caused by?

Answer 23

Vasomotion

Question 24

Vasomotion?

Answer 24

Spontaneous movement back and forth in tone of blood vessel walls, independent of heart beat, innervation or respiration
- When there are increased O2 levels, muscle contracts
- When there are decreased O2 levels, muscle relaxes
(Vasodilation and Vasoconstriction)

Question 25

Are the metarterioles and precapillary sphincters enervated?

Answer 25

No, they're innervated

Question 26

What are the two main factors that blood consists of?

Answer 26

Fluid plasma and the blood cells

Question 27

Plasma?

Answer 27

Plasma is a watery fluid containing about 8% solids, 92% water

Question 28

Plasma?

Answer 28

- Plasma is a watery fluid containing about 8% solids, 92% water - Made of protein and interstitial fluid

Question 29

What are the four pressures involved in fluid exchange in the capillary bed?

Answer 29

Inside the capillary: 2 opposing pressures 1. Capillary hydrostatic pressure, 25 mmHg -tends to force fluid out; Is different in arterial or venous capillaries 2. Plasma colloid osmotic pressure, 28 mmHg - sucks fluid back in Outside the capillary (within the tissue): 2 additive pressures 1. Interstitial fluid pressure, 6.3 mmHg -[negative] sucks fluid out 2. Interstitial fluid colloid osmotic pressure, 5 mmHg - fluid out

Question 30

Interstitial fluid pressure?

Answer 30

- Is negative bc it creates a force for fluid to enter the tissue

Question 31

Blood flow of oxygenated/de-oxygenated blood starting with capillaries?

Answer 31

- Oxigenated blood goes from artery capillaries to tissue | - De-oxygenated blood goes from tissue into vein capillaries

Question 32

What is the lumen of a blood vessel?

Answer 32

The interior of a vessel, such as the central space in an artery, vein or capillary through which blood flows

Question 33

Metarterioles?

Answer 33

- Branch off of arterioles - No continuous smooth muscle coat - The blood goes from the metarteriols, through the precapillary sphincters to the capillaries

Question 34

Function of the precapillary sphincters?

Answer 34

Closes off circulation to capillary beds

Question 35

What are the two opposing pressures inside the capillary?

Answer 35

1. Capillary hydrostatic pressure - Forces fluid out + - Different in arterial and venous capillaries 2. Plasma colloid osmotic pressure - Sucks fluid into the capillaries

Question 36

What are the 2 additive pressures outside the capillaries (in the tissues)?

Answer 36

1. Interstitial fluid pressure - Sucks fluid out of the capillaries into the tissue 2. Interstitial fluid colloid osmotic pressure - Sucks fluid out of the capillaries into the tissue

Question 37

What are the two main components of blood?

Answer 37

- Plasma fluid | - Blood cells

Question 38

What are the main proteins in the plasma?

Answer 38

- Albumin (most) - Globulin (second most) - Fibrinogen (least)

Question 39

What are some main components of plasma?

Answer 39

Proteins, organic material, inorganic material, hormones, etc

Question 40

Three types of blood cells?

Answer 40

- Erythrocytes - Leukocytes - Platelets

Question 41

Function of erythrocytes?

Answer 41

- Transport O2 and CO2 - Red cells - Main component

Question 42

Function of leukocytes?

Answer 42

- Protect against infection | - White cells

Question 43

Function of platelets?

Answer 43

- Allow for clotting | - Thrombocytes