Lecture #7 Flashcards Preview

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Flashcards in Lecture #7 Deck (34):
1

Flow is governed by two main variables, what are they?

1. Pressure
- impels fluid to move
- According to pressure gradient (high to low)

2. Resistance
- opposes flow

2

Auscultation

Listening to sounds made by the body

3

S1 Lub

AV valves

4

S2 (Dub)

SL Valves

5

Pulmonary Edema

1. Right Ventricle output exceeds left ventricle output
2. Pressure backs up
3. Fluid accumulates in pulmonary tissue

6

Systemic Edema

1. Left Ventricle output exceeds right ventricle output

2. Pressure backs up

3. Fluid accumulates in systemic tissue

7

Cardiac Output

CO=HR(SV)
Volume of blood pumped per unit time

8

Cardiac Output can be modified by either term:

1. Heart Rate (HR)
- Modulated by nervous and endocrine system
- bradycardia (<60bpm)
- Tachycardia (>100bpm)

2. Stroke Volume (SV)
- volume of blood pumped with each beat
- preload, contractility, and after load

9

Heart rate is regulated by?

Cardiac centers in the Medulla of the brain
1. Proprioceptors are responsible for activating muscles and joints

2. Baroreceptors (pressure receptors)
are responsible for detecting changes in blood pressure, include the aorta and internal carotid arteries

3. Chemoreceptors are responsible for detecting blood pH, CO2, and O2, in Aortic arch, carotid arteries, medulla

10

Autonomic Nervous systtem

- influence the rate of impulse generation (firing), depolarization/depolarization of myocardium

- Influence strength of atrial and ventricular contraction

- influence changes in the heart and circulatory system faster than metabolic or humoral agents

11

Vagal Tone

Parasympathetic, slower heart rate between 70-80bpm

- if all sympathetic and parasympathetic stimulations or nerves are damage heart will continue beating at 100bpm

12

Blood Flow

- the amount of blood flowing through an organ, tissue, or blood vessel in a given time (mL/min)

13

Perfusion

the passage of fluid per given volume or mass of tissue in a given time (mL/min/g)

14

Flow of blood thought the body

- is constant and is equal to the cardiac output (5.25L/min)
- flow through individual organs varies from minute to minute

15

Hemodynamics

Physical principles of blood flow based on pressure and resistance

1. the greater the difference between two points, the greater the flow
2. the greater the resistance = less flow

16

Blood Pressure

is the force that blood exerts against a vessel wall

BP declines with distance from the heart
- arterial elasticity
- friction on vessel wall

17

Where is Blood Pressure measured?

Normal Value

brachial artery of the arm using sphymomanometer

= 120/75mmHg

18

Two pressures are recorded

1. Systolic Pressure - peak arterial BP taken during ventricular contraction

2. Diastolic Pressure - minimum arterial BP taken during ventricular relaxation (diastole)

19

Pulse Pressure

difference between systolic-diastolic pressure

20

Mean Arterial Pressure (MAP)

- the mean pressure, takes measurements at several intervals throughout the cardiac cycle

MAP = diastolic pressure + 1/3 (Pulse Pressure)

21

What is Atherosclerosis?

Fat build up inside the arteries (plaque)

- progressive conditions lead to coronary artery disease and peripheral artery disease

22

Define Hypertension

High blood pressure
BP>140/90
- can weaken arteries, cause aneurysms, promote atherosclerosis

23

Define Hypotension

chronic low resting BP
- caused by blood loss, dehydration and anemia

24

What are the factors contribute to blood pressure

1. Cardiac Output - the amount of blood pumped out by the heart per minute

2. Blood Volume
- regulated by the kidneys

3. Resistance to Flow

25

Peripheral Resistance

the opposition to flow that blood encounters in vessels away from the heart

26

What are the factors that influence resistance?

1. Blood Viscosity (Thickness)
- increased mainly from RBC count and albumin

2. Vessel length
- more friction it encounters the father it goes
- pressure and flow declines with distance

3. Vessel Radius
- most powerful influence over flow

27

Laminar Flow

flows in layers, faster in the center.

small changes in blood vessel radius can cause large change in flow

28

Vasoconstriction

when smooth muscle of tunica media contracts

29

Vasodilation

relaxation of the smooth muscle, allowing blood pressure to expand vessel

30

Peripheral Resistance
Aorta to capillaries

Blood velocity decreases from aorta --> capillaries because:

1. increase distance = more friction -- lower speed

2. decreased radii of vessels = more resistance

3. Greater corss-sectional area because the # of vessel increase

31

Peripheral Resistance From capillaries -- > vena cava velocity increase because:

1. Veins are larger = less resistance than capillaries

2. Convergence of vessels large amounts of blood into smaller channels

BLOOD IN VEINS NEVER REGAIN VELOCITY IT LOST

32

Vasoreflexes

are quick and powerful ways of regulating blood pressure and flow

33

Two purposes of dilation and constriction are?

1. General control of BP throughout the whole body

2. Method of rerouting blood from one region to another for perfusion of individual organs

34

What are the 3 ways of controlling vasomotor activity?

1. Local Control
2. Neural Control
3. Hormonal Control