Cardiovascular physiology Lecture 1

Question 1

What is hemodynamics?

Answer 1

The study of blood flow

Relates Ohm’s law to fluid flow, looking at the relationship between blood flow, blood pressure and resistance

Question 2

What is resistance to blood flow?

Answer 2

The friction that impedes flow, or how difficult it is for blood to move between 2 points at any given pressure

Question 3

What formula describes flow?

Answer 3

Flow = change in pressure divided by resistance

Question 4

Blood flow is related to the _______ between two fixed points and is inversely proportional to the _____

Answer 4

Blood flow is related to the pressure difference between two fixed points and is inversely proportional to the resistance

Question 5

Blood always flows from a region of high ____ to a region of low ______

Answer 5

Blood always flows from a region of high pressure to a region of low pressure

Question 6

For blood to flow, the change in pressure must be larger than _____

Answer 6

Resistance

Question 7

What is the major mechanism for changing blood flow?

Answer 7

To alter the resistance of blood vessels in particular arterioles

Question 8

What is hydrostatic pressure?

Answer 8

Blood hydrostatic pressure is the pressure that the volume of blood within our circulatory system exerts on the walls of the blood vessels that contain it

Often called “pressure”

Question 9

If there is no pressure difference, what is the rate of flow?

Answer 9

0 ml/min

Question 10

What are three factors that determine resistance to blood flow?

Answer 10

1. viscosity of the blood
2. length of the blood vessel
3. diameter of the blood vessel

Question 11

What is viscosity? And what effects viscosity of blood?

Answer 11

• The friction between molecules of a flowing fluid
• Hematocrit (#of RBC in blood) affects viscosity

Question 12

What is poiseuilles’s equation for R?

Answer 12

R= 8nL/πr⁴

Question 13

Resistance to flow is directly proportional to the ___\_of the ____\_ and the ______\_ and inversely proportional to the _____ of the vessel

Answer 13

Resistance to flow is directly proportional to the length of the vessel and the blood viscosity and inversely proportional to the radius of the vessel

R=8nL / pir⁴

Question 14

What factor has the greatest effect on resistance?

Answer 14

Vessel Diameter (changed via constriction/relaxation of vascular smooth muscle)

very small changes in vessel diameter lead to large changes in resistance

Question 15

What is the effect of a closed circulatory system on pressure?

Answer 15

Closed circulatory system allows for greater pressures to be generated when the heart contracts

Question 16

small branching vessels with high resistance

Answer 16

arterioles

Question 17

transport of blood between small arteries and veins; exchange of materials between blood and cells in the body

Answer 17

capillaries

Question 18

carry blood away from the heart

Answer 18

arteries

Question 19

carry blood toward the heart

Answer 19

veins

Question 20

• Thin walled chambers
• low-pressure chambers
• receive blood returning back to the heart

Answer 20

atria

Question 21

• thick walled chambers
• responsible for the forward propulsion of blood when they contract

Answer 21

ventricles

Question 22

Lowest superficial surface of the heart

Answer 22

Apex

Question 23

what separates left and right atria

Answer 23

Interatrial septum

Question 24

What separates left and right ventricles?

Answer 24

Interventricular septum

Question 25

Upper surface of the heart where the blood vessels attach:

Answer 25

Base

Question 26

What feature of the heart allows it to function as a dual pump?

Answer 26

Separation of the left and right sides (via interatrial and intraventricular septa)

Question 27

The fibrous sac surrounding the heart and roots of great vessels:

Answer 27

Pericardium

Question 28

What are four functions of the pericardium?

Answer 28

1. Stabilization of the heart in thoracic cavity
2. protection of the heart from mechanical trauma, infection
3. secretes pericardial fluid to reduce friction
4. limits overfilling of the chambers, prevents sudden distension (resist large change in size)

Question 29

What are the three layers of the pericardium?

Answer 29

1. Fibrous pericardium
2. Parietal pericardium
3. Visceral pericardium (epicardium)

Question 30

What is the serous pericardium?

Answer 30

Collective name for the parietal and visceral pericardium

Question 31

What is the pericardial cavity?

Answer 31

space between the parietal pericardium and the visceral pericardium both of which secrete serous fluid to decrease friction between the meembranes

Question 32

WHat is the serous layer?

Answer 32

a layer composed of cells that secrete a fluid

Question 33

Inflammation of pericardium

Answer 33

Pericarditis

Question 34

What does pericarditis lead to?

Answer 34

Inflammtion of pericardium caused by viruses, bacteria, fungi, trauma or malignancy which leads to fluid accumulation in the pericardial cavity

Question 35

What is Cardiac tamponade?

Answer 35

Compression of heart chambers due to excessive accumulation of pericardial fluid = limits heart movement and chambers cannot fill with adequate amount of blood (ie decreases ventricular filling)

Question 36

What are the three layers of the heart wall?

Answer 36

1. epicardium (visceral pericardium)
2. myocardium
3. endocardium

Question 37

Layer immediately outside the heart muscle is the _______ which is connected to the myocardium via ______ and functions as a:

Answer 37

Layer immediately outside the heart muscle is the epicardium (visceral pericardium) which is connected to the myocardium via connective tissue and functions as a: Protective layer

Question 38

The muscular wall of the heart that lies beneath the epicardium is the:

What does it contain (2)

Answer 38

Myocardium

• Contains:
  
  • muscle cells (myocytes) which contract and relax as heart beats
  • nerves and blood vessels

Question 39

What is the endocardium?

Answer 39

Innermost layer of the heart wall

• lines heart cavities and the heart valves;
• thin layer of endothelium which is continuous with the endothelium of the attached blood vessels

Question 40

The ventricles have thicker _______ than the atria, with the left having thicker than the right

Answer 40

The ventricles have thicker myocardium than the atria, with the left having thicker than the right

Question 41

Cardiac muscle cell

Answer 41

myocyte

Question 42

interdigitated region of attachment - holds adjacent cells together

Answer 42

Intercalated disc

Question 43

Two types of specialized intercellular junctions at intercalated disks

Answer 43

1. Desmosomes
2. gap junctions

Question 44

What is a desmosome?

Answer 44

• Adhering junction that hold cells together in tissues subject tot considerable mechanical stress or stretching
• mechanically couple one heart cell to another
• involves proteins:
  
  • cadherins
  • plaques
  • intermediate filaments

Question 45

What is a gap junction?

Answer 45

• communicating junction
• electrically couple heart cells, allowing ions to move between cells
  
  • important for spread of AP
• Proteins:
  
  • connexons

Question 46

When the cardiac muscle contract and shorten it comes together link a squeezing fist (wringing) efficiently pushing blood up. Why?

Answer 46

The myocardium consists of interlacing bundles of cardiac muscle fibres arranged spirally around the circumference of the heart