Week 5

Question 1

What is myogenic of arterial diameter?

Answer 1

an increase in pressure leads to muscle stretch and then a recoil by constriction (this is the myogenic response)

Question 2

what are neural controls to regulate diameter and flow of arteries?

Answer 2

• vasoconstrictors: sympathetic nerves that release norepinephrine
• vasodilators: parasympathetic nerves - neurones that release nitric oxide

Question 3

what are the hormonal controls to regulate blood flow?

Answer 3

vasoconstrictors- Epinephrine & vasopressin
vasodilators- epinephrine
** 2x but different receptor

Question 4

what are local controls in changing blood flow?

Answer 4

• vasoconstrictors: internal blood pressure & endothelin
• vasodilators: decrease in oxygen, increase c02, h & k, adenosine, during injury,

Question 5

what is a tonic state?

Answer 5

• arterial smooth smooth are partially contracted

Question 6

what are the properties of capillaries?

Answer 6

• numerous
• large SA
• thin
  ** for diffusion

Question 7

What is flicks law of diffusion

Answer 7

Question 8

What is flicks law of diffusion

Answer 8

Question 9

what is important about the total cross sectional area of capillaries?

Answer 9

• it dictates the velocity of blood flow
• provides enough time for diffusion to reach equilibrium

Question 10

describe the types of capillaries?

Answer 10

• continuous: endothelial cells tightly packed (muscle, nerve, fat)
• fenestrated: allow for open and close
  (Glands, kidneys, intestines)
• discontinuous: where blood cells are produced so they can enter circ. system (spleen, bone marrow, liver)

Question 11

what are the types of transport?

Answer 11

diffusion- oxygen & c02
vesicle transport (active transport) - larger molecules like proteins
bulk flow- water and solutes

Question 12

what are the properties of veins?

Answer 12

Question 13

what is the difference between healthy and diseased veins?

Answer 13

healthy- contain valves to prevent back flow of blood
unhealthy- causes blood to accumulate at extremities

Question 14

what is venous return?

Answer 14

the driving pressure caused by the difference in central venous pressure and right atrial pressure

Question 15

what are veins affected by?

Answer 15

veins are affected by hydrostatic pressure which opposes load flowing towards the heart

Question 16

how does the diameter of veins change?

Answer 16

• The diameter of veins is affected by blood circulating epinephrine
• The sympathetic stimulation releases norepinephrine to the veins smooth muscle which displaces the blood to the heart

Question 17

what is the skeletal muscle pump?

Answer 17

• Pressure in distal veins falls & so skeletal muscle contracts to push blood back to the heart

Question 18

how does the respiratory pump affect inspiration and expiration?

Answer 18

Inspiration- intrathoracic pressure decreases and intrabdominal pressure increase
Expiration- intrathroracic pressure increases and intrabdominal pressure decrease

Question 19

What pressure changes occur in inspiration and expiration

Answer 19

Pressure changes in the thoracic cavity and abdominal cavity

Question 20

what do lympth vessels do

Answer 20

• Lymph vessels collect filtered fluid from the interstitial space and return it to the circulating blood system

Question 21

What is lympth composition

Answer 21

Lymph composition is similar to plasma with a lower protein content

Question 22

what is oedema

Answer 22

• accumulation of excess fluid in the intestinal space due to
• increased capillary hydrostatic pressure
• decrease plasma osmotic pressure

Question 23

what are the functions of the cardiovascular system?

Answer 23

• Transports oxygen, nutrients and metabolites and removes waste products and
• Distributes hormones and secrets some hormones
• Involvement in homeostasis and regulates body temp

Question 24

What are the two circulatory systems

Answer 24

1• pulmonary- connects heart and lungs in series, always enough blood
2• Systemic- connects heart and body in parallel, not always enough blood to support needs so is distributed

Question 25

what are the properties of fluid (blood)

Answer 25

• fluids are incompressible - the blood cannot be squeezed into a smaller volume • blood fluid moves by a driving pressure = the pressure between 2 points (moves from high to low) • Darcys law - the flow depends on pressure difference not the highest amounts of pressure

Question 26

what is Darcy’s law

Answer 26

Question 27

what is poiseuilles law

Answer 27

Question 28

how is flow related to pressure and radius?

Answer 28

Question 29

how does the cross section area affect flow?

Answer 29

Question 30

What is the cross sectional area a measure of?

Answer 30

Question 31

What is the cross sectional area a measure of?

Answer 31

Question 32

What are the bottom and top of heart called?

Answer 32

- Left side of heart is slightly smaller to make room for the heart - The bottom on the heart is the apex of the heart (point part) - The top of the heart is the base

Question 33

what are the external parts of the heart?

Answer 33

External Parts of the heart: • coronary circulation • pericardium - fibrous sac surrounding heart to Protects the heart Provides lubrication Attaches to diaphragm to keep it in place

Question 34

What are the internal parts of the heart

Answer 34

Question 35

what are the parts of cardiac muscle

Answer 35

Question 36

compare skeletal and cardiac muscle

Answer 36

Question 37

what is the difference in the contractions in skeletal and cardiac muscle

Answer 37

Question 38

what is the signal propagation in the heart?

Answer 38

- the electrical signals in the heart causing contractions originate from gap junctions

Question 39

What are the components of arteries

Answer 39

Adventitia - • provides structure strength (for high pressures) • in large vessels (aorta) the adventitia contain small blood vessels Elastin - • Allows vessel to expand & recoil - regulates blood pressure Endothelium - • forms lumen • filters between the blood & the body • secretes vasoactive products - hormones Smooth muscle • contractile power Pre-capillary sphincters - • controls blood flow to specific capillaries • squeezes vessel so resistance increases & blood is diverted

Question 40

What is mean arterial pressure

Answer 40

• the average blood pressure during a cardiac cycle • the blood flow changes in pressure at different parts of the body in order to distribute the blood → but arterial pressure is maintained

Question 41

what is active hyperaemia & what causes it?

Answer 41

an increase in blood flow according to the metabolic needs of the tissue

Question 42

what is flow auto regulation and how is it maintained?

Answer 42

= the maintenance of blood flow. So when blood pressure drops vessels constrict & when blood pressure rises the blood vessels dilate (the driving force decreases) + increased blood pressure causes blood flow to rise so vasodilator is removed and vasoconstrictor occurs so flow returns to normal (as flow increases, pressure decreases)