Chapter 14 Cardiac Output, Blood Flow and Blood Pressure

Question 1

SA norde rhythmically excited at how many bpm

Answer 1

100bpm

pacemaker potential

Question 2

What 2 ways does the Parasympathetic nervous system control on heart rate…

Answer 2

Resting state 70-75 bpm

ACh release from Parasympathetic nervous system causes heart rate lower than 100bpm

In addition to this, increase permeability to K results in slower rate of depolarisation

Question 3

What 3 ways does the Sympathetic nervous system control on heart rate

Answer 3

1. NE from sympathetic nervous system and E from adrenal medulla bind to Beta-Adrenergic receptors in SA node to increase heart rate
2. Increase permeability of HCN channels = faster rate of depolarisation = increase heart rate
3. Increase contractility and faster contraction and relaxation

Question 4

How is the SA node effected by autonomic nerve activity

Answer 4

1. Sympathetic: Increased rate of diastolic depolarisation = Increase cardiac rate
2. Parasympathetic: Decrease rate of diastolic depolarisation = decreased cardiac rate

Question 5

How is the AV node effected by autonomic nerve activity

Answer 5

1. Sympathetic: Increased conduction rate

2. Parasympathetic: Decreased conduction rate

Question 6

How is the Atrial muscle effected by autonomic nerve activity

Answer 6

Sympathetic: Increased strength of contraction

Question 7

How is the Ventricular muscle effected by autonomic nerve activity

Answer 7

Sympathetic: Increased strength of contraction

Question 8

What happens if EDV (Preload) increases

Answer 8

Greater Stroke volume

Because Frank-Starling law of heart

Question 9

What is resistance

Answer 9

Impedance to blood flow

Question 10

What happens if total peripheral resistance (afterload) increases

Answer 10

Greater pressure in the arterial system
Increased afterload
Lower Stroke volume

Question 11

What happens when there is a greater arterial pressure

Answer 11

Increased after load

Therefore, heart must work harder to eject blood

Question 12

What are the 3 ways stroke volume is regulated

Answer 12

1. EDV
2. TPR
3. Contractility

Question 13

How does contractility regulate stroke volume

Answer 13

Sympathetic system and adrenal medulla release E and NE to increase ventricular contractility = increase stroke volume

Question 14

What is Frank-Starling law of the heart

Answer 14

As EDV increases so does stroke volume

Question 15

At rest is the cardiac muscle length short or long

Answer 15

Short

Question 16

With a greater EDV there is greater…

Answer 16

stretch = cardiac muscle length

Question 17

What does a greater muscle length result in

Because

Answer 17

Increases strength of contraction

Because there is:

1. Optimal alignment of actin and myosin
2. Increased release of Ca from SR

Question 18

EDV is effected by…

Answer 18

venous return

Question 19

What does an increase in peripheral resistance do to Frank-Starling law

Answer 19

1. Increase peripheral resistance decreases SV
2. More blood remains in ventricle = increases EDV
3. Increase stretch
4. Stronger contraction to eject blood

Question 20

Cardiac output =

Answer 20

Cardiac rate x stroke volume

Question 21

What 3 main ways can you increase stroke volume

Answer 21

Increase:
EDV
NE delivery
E delivery

(Decrease):
Peripheral resistance

Question 22

What 3 main ways can you increase heart rate

Answer 22

Increase:
NE delivery
E delivery

Decrease:
Parasympathetic

Question 23

Sympathetically mediated venoconstriction can increase what

Answer 23

venous return to the RIGHT side of the heart

Question 24

Extracellular fluid represents how much of the total bodies water

How much of that is made up of blood and ISF

Answer 24

1/3 of total body

This 1/3 is made up of 20% blood and 80% ISF

Question 25

What pressure causes fluid to filter out of vessels into the ISF

Answer 25

Blood pressure

Question 26

What pressure causes water to be absorbed from tissues to vessels

Answer 26

Osmotic pressure

Question 27

Blood volume is regulated by... (3)

Answer 27

1. Drinking 2. Urine volume 3. Distribution of water between plasma and ISF

Question 28

How do the kidneys play a role in blood volume

Answer 28

1. Urine is derived from blood plasma | 2. ADH and Aldosterone act on kidneys to regulate blood volume

Question 29

How is water lost by the body (4)

Answer 29

1. Excretion of urine 2. Exhalation of air 3. Sweating 4. Faeces

Question 30

What is filtration

Answer 30

movement of fluid and solutes OUT of the blood

Question 31

What is absorption

Answer 31

movement of fluid and solutes INTO the blood

Question 32

What pressure causes filtration of fluid out of capillaries

Answer 32

Hydrostatic pressure

Question 33

What is the hydrostatic pressure at the: Arteriolar end Venular end of systemic capillaries

Answer 33

``` Arteriolar = 37 mm Hg Venular = 17 mm Hg ```

Question 34

Why is ISF hydrostatic pressure low

Answer 34

Due to drainage into lymphatic vessels

Question 35

What substances are filtered with the fluid

Answer 35

Solutes such as glucose, salts, ions

Question 36

What substance is lower in the ISF compared to plasma Why

Answer 36

Protein To big to fit through capillary pores

Question 37

What is the Net filtration pressure

Answer 37

Hydrostatic pressure of capillary blood minus hydropstatic pressure of ISF

Question 38

3 rules of starling forces

Answer 38

1. There is a constant interchange of plasma and ISF 2. Difference between capillary hydrostatic pressure and ISF hydrostatic pressure favours filtration OUT of capillary 3. Water concentration difference between plasma and ISF favours absorption of ISF INTO capillary

Question 39

What happens to hydrostatic pressure as blood travels further from the heart

Answer 39

Decreases

Question 40

What happens to osmotic pressure along the capillary

Answer 40

Remains constant

Question 41

Renal hormones affect...

Answer 41

Reabsorption Therefore: Urine and blood volume

Question 42

What happens if there is more reabsorption

Answer 42

Less urine output | Increase blood volume

Question 43

What happens if there is less reabsorption

Answer 43

More urine output | Decreased blood volume

Question 44

When is ADH released

Answer 44

when hypothalamic osmoreceptors detect an increase in plasma osmolarity This causes increase water retention

Question 45

What does Aldosterone do

Answer 45

Promotes retention of salt This increases water retention

Question 46

Dyhydration or excessive salt intake leads to what sensation and what effect What is the response

Answer 46

Thirst Increase blood osmolarity ADH produced to retain water

Question 47

What does salt deprivation cause What is the response

Answer 47

low blood volume low blood pressure Increase salt and water retention by kidney

Question 48

What is the process of Natriuresis

Answer 48

Excretion of sodium in urine

Question 49

What hormone is produced by the atria What does it do What stimulates the hormone What is the final result

Answer 49

Atrial Natriuretic Peptide (ANP) Increases Na and Water excretion in urine Stretching of the atria Increase urine volume = reduces blood volume

Question 50

What is resistence directly proportional with

Answer 50

Length of vessel | Blood Viscocity

Question 51

What is resistance inversely proportional with

Answer 51

Vessel radius

Question 52

Unequal resistances to blood flow cause

Answer 52

Co2 to be distributed unequally

Question 53

Blood flow is determined by...

Answer 53

the pressure difference between MEAN PRESSURE and PRESSURE AT END OF CIRCUIT

Question 54

What happens to pressure as distance increases

Answer 54

decreases

Question 55

Mean Arterial pressure =

Answer 55

CO X TPR

Question 56

What are the 3 main ways of regulating blood flow

Answer 56

Extrinsic control Intrinsic control Paracrine control

Question 57

What are the ways of vasocontricting (2)

Answer 57

1. Sympathetic stimulation (NE) of alpha-adrenergic receptors 2. ADH production

Question 58

What are the ways of vasodilating (3)

Answer 58

1. Sympathetic stimulation (E) of beta-adrenergic receptors 2. ACh release by sympathetic neurons (skeletal muscle aterioles) 3. Parasympathetic activity

Question 59

How does paracrine control work

Answer 59

Nitric oxide - vasodilates vessels

Question 60

What are the two intrinsic controls

Answer 60

Flow autoregulation | Active hyperemia

Question 61

What is flow autoregulation

Answer 61

Maintains constant blood flow: 1. via vasodilation when BP drops 2. via Vasocontriction when BP increases

Question 62

What is active hyperemia

Answer 62

Local vasodilation when metabolism increases

Question 63

What is the baseline of Co2

Answer 63

5L/min

Question 64

During exercise there is an increase in.. Which increases...

Answer 64

Metabolism Vasodilation

Question 65

During exercise what happens to allow for more blood to flow to skeletal muscles

Answer 65

Vasocontriction of GI system and kidneys via sympathetic activity

Question 66

Training can do what on the heart rate and SV Why

Answer 66

Lower HR because of greater parasympathetic inhibition of SA node Increase SV because of increased blood volume

Question 67

Resistance is greatest where Why

Answer 67

Arterioles To reduce blood flow and pressure in capillaries This increases arterial blood pressure

Question 68

A large capillary cross sectional area causes

Answer 68

further reduction in blood flow and pressure

Question 69

Increases in SV, HR and or CO have what effect on blood pressure

Answer 69

increases

Question 70

What do kidneys control in the cardiac system

Answer 70

Blood volume | SV

Question 71

What does sympathetic NS do Which does what

Answer 71

Stimulates vasocontriction Which increases: 1. Blood pressure 2. Co2

Question 72

What does a Baroreceptor reflex do

Answer 72

Maintains blood pressure

Question 73

What does contriction in the arterioles have an effect on arteries and capillaries/veins

Answer 73

Arteries = increases pressure UPSTREAM Capillaries/veins = decreases pressure DOWNSTREAM

Question 74

What are Baroreceptors What do they maintain

Answer 74

Stretch receptors Maintain MAP

Question 75

Where are Baroreceptors located

Answer 75

Aortic arch | Carotid sinuses of heart

Question 76

Baroreceptors AP frequency is directly proportional to what

Answer 76

Mean Arterial Pressure

Question 77

What is Hypotension

Answer 77

Low blood pressure

Question 78

What is main effect in Hypotension

Answer 78

Reduces blood flow to brain and cardiac muscle

Question 79

What are some of the causes of hypotension

Answer 79

``` CV disease Dehydration Neural/endocrine defects Medication Hemorrhage ```

Question 80

What is the response to hypotension

Answer 80

Baroreceptor reflex

Question 81

What is Hypertension

Answer 81

Chronic high blood pressure Above 140/90 mm Hg

Question 82

What results from hypertension

Answer 82

Left ventricle must pump against increase arterial pressure Leads to heart failure

Question 83

What are some of the causes of hypertension

Answer 83

Genetic/environmental (primary) Arteriosclerosis (secondary) Endocrine disorder (secondary)

Question 84

``` What values are considered for: Normal Prehypertension Stage 1 Hypertension Stage 2 Hypertension ```

Answer 84

Normal = Under 120/80 Prehypertension = 120-140/80-90 Stage 1 Hypertension = 140-160/90-100 Stage 2 Hypertension = Over 160/100

Question 85

What are some of the ways to treat for hypertension

Answer 85

``` Reduce: Smoking Alcohol Sodium intake Weight ``` Increase: Potassium Exercise Medication

Question 86

What is heart failure

Answer 86

Heart doesnt pump an adequate cardiac output to maintain blood flow

Question 87

What does a low cardiac output lead to

Answer 87

Increase fluid retention = increased blood volume + SV Increase hypertrophy of ventricles = however failing heart cant handle large EDV

Question 88

What causes heart failure

Answer 88

Heart attack Hypertension Valve insufficiency Structural damage to coronary