Lecture 16 - Circulatory Control Systems

Question 1

An abnormal increased volume of interstitial fluid in a tissue or organ is called:

Answer 1

Edema

Question 2

True or false: under normal conditions, the volume of a tissue remains constant except for minor variation of capillary blood volume

Answer 2

True

Question 3

How is Interstitial fluid volume controlled?

Answer 3

hydrostatic pressure
osmotic pressure
endothelial integrity
the lymphatic system

Question 4

What are the causes of Edema?

Answer 4

-endothelial damage (inflammation)
-impaired lymphatic drainage
-raised blood pressure
-reduced blood osmotic pressure
-increased capillary permeability
-decreased plasma protein

Question 5

What is the significance of albumin in regards to edema?

Answer 5

Albumin helps to retain water within the blood vessels by drawing water into the bloodstream from the surrounding tissues. A decrease in albumin concentration in the blood will result in a consequent decrease in blood osmotic pressure. This effectively lowers the osmotic pressure gradient, and less water will be drawn out of the tissues and into the blood, leaving it to accumulate in the tissues and cause edema.

Question 6

How does cardiac/renal failure cause edema?

Answer 6

It raises blood hydrostatic pressure, and fluid will move down the pressure gradient into the surrounding tissues, where the hydrostatic pressure is lower.

Question 7

What are three reasons for reduced blood osmotic pressure?

Answer 7

• Renal disease (loss of albumin across glomerulus)
• hepatic disease (inadequate albumin synthesis)
• malnutrition (inadequate albumin synthesis)

Question 8

What are some causes of lymphatic obstruction that can lead to edema?

Answer 8

Tumors, fibrosis, inflammation, surgery, congenital abnormality

Question 9

In order to maintain homeostasis in the cardiovascular system and respond to changes in activity, blood flow must be:

Answer 9

redirected to the tissues that become more active to provide enough supply

Question 10

What is the only organ that receives a (relatively) constant supply of blood?

Answer 10

the brain

Question 11

What controls cardiovascular function by adjusting HR, stroke vol, pressure, distribution, etc?

Answer 11

negative feedback systems of the Neural, Endocrine, and autoregulatory systems

Question 12

Autoregulation of perfusion in the capillary bed is (dependent/independent) of specialized nervous stimulation or endocrine control

Answer 12

independent

Question 13

When the body is active, does blood pH increase or decrease?

Answer 13

It decreases, because cells undergo cellular respiration to met the energy requirements, which creates more CO2, and subsequently H+

Question 14

Increased CO2, decreased O2, increased K+, adenosine, lactate, decreased local pH, or increased local temperature will all stimulate the release of:

Answer 14

NO from the endothelial cells, which is a powerful vasodilator

Question 15

decreased CO2, increased O2, increased pH, and decreased local temperature will stimulate the release of:

Answer 15

endothelins from the endothelial cells, which are powerful vasocontrictors

Question 16

what happens when the precapillary sphincters contract?

Answer 16

Blood flows only through the thoroughfare channel, restricting passage to the rest of the capillary bed. This DECREASES blood flow

Question 17

What happens when the precapillary sphincters are relaxed?

Answer 17

blood flows throughout the entire capillary bed, effectively INCREASING blood flow.

Question 18

during vasodilation, the precapillary sphincters are:

Answer 18

relaxed

Question 19

during vasocontriction, the precapillary sphincters are:

Answer 19

constricted

Question 20

When blood flow is excessively high and the vessels are excessively stretched, the smooth muscle cells of the vessel can reflexively contract and decrease blood flow to that area. This is known as the:

Answer 20

Myogenic response

Question 21

If perfusion of an organ is too low (ischemia), the tissue will experience low levels of oxygen (hypoxia). The vessel’s smooth muscle will be only minimally stretched. In response, it relaxes, allowing the vessel to dilate and
thereby increase the movement of blood into the tissue. This is known as:

Answer 21

The myogenic response

Question 22

walls of the systemic blood vessels (dilate/constrict) in response to low O2, while the walls of the pulmonary blood vessels (dilate/constrict) under low O2

Answer 22

systemic = dilate, pulmonary = constrict

Question 23

The cardiovascular center of the brain is found in the:

Answer 23

medulla

Question 24

The inputs of the cardiovascular center in the brain are the _____ while the outputs are the _______

Answer 24

Input: cerebral cortex, limbic system, hypothalamus, sensory receptors (baro/chemo) in the periphery

Output: Autonomic NS

Question 25

What are the main types of sensory receptors for cardiovascular regulation?

Answer 25

Baroreceptors within the blood vessels and heart chambers that respond to blood pressure Chemoreceptors near the baroreceptors that monitor concentration of H, CO2, O2

Question 26

The ______ centers slow cardiac function by decreasing heart rate via parasympathetic stimulation from the vagus nerve

Answer 26

cardioinhibitor

Question 27

The ______ centers stimulate cardiac function by increasing heart rate and stroke volume via sympathetic stimulation from the cardiac accelerator nerve

Answer 27

cardioaccelerator

Question 28

The ________ control contraction of the smooth muscle in the blood vessel, via sympathetic stimulation from the vasomotor nerve.

Answer 28

vasomotor centers

Question 29

Sympathetic stimulation _____ blood pressure, and parasympathetic _________ blood pressure

Answer 29

increases, decreases

Question 30

increased BP results in ___ baroreceptor firing, ____ stimulation of cardiac inhibitor centers, ______ stimulation of cardiac accelerator and vasomotor centres, ____ cardiac output, and ____ vasodilation

Answer 30

- higher baroreceptor firing - increased cardiac inhibitor -decreased accelerator and vasomotor - decreased cardiac output - increased vasodilation

Question 31

Describe the neural response to decreased blood pressure

Answer 31

baroreceptors fire less, causing increased stim of the accelerator and vasomotor centers and decreased stim of the inhibitor centers. this results in higher cardiac output (HR, SV), and increased vasoconstriction, causing blood pressure to rise

Question 32

What is the chemoreceptor reflex?

Answer 32

Chemoreceptors detect hypoxia (low O2), hypercapnia (high co2), acidosis (high H+), and send signals to the cardiovascular center in the brain

Question 33

how does the CV respond to hypoxia?

Answer 33

increased oxygen uptake by increasing respiratory activity and ventilation, while also increasing oxygen conservation by causing vasoconstriction (via sympathetic vasomotor activity) and decreased HR and cardiac work (via cardiac vagal activity)

Question 34

T/F. Parasympathetic innervation is important in the heart and the vasculature

Answer 34

False. It is important in the heart, but not so much in the vasculature

Question 35

Explain how the sympathetic division of neurons work

Answer 35

The preganglionic neurons release ACh at the synapse to bind to the nicotinic receptors on the postganglionic neurons. then the postganglionic sympathetic neurons release NE from their nerve terminals to bind the adrenergic receptors on the target tissues.

Question 36

Explain how the parasympathetic division of neurons work

Answer 36

the preganglionic neurons release ACh at the synapse to bind the nicotinic receptors on the postganglionic neurons. Then the post neurons release ACh from their nerve terminals to bind to the muscarinic receptors on the cell membrane tissues

Question 37

Heart rate and body size are _____ related

Answer 37

inversely. This is because smaller animals have a greater metabolic rate due to a higher SA:VOL ratio

Question 38

Epinephrine and Norepinephrine are released by the adrenal medulla, and increase HR and force of contraction by acting on what type of receptor?

Answer 38

B1

Question 39

During exercise, what happens to oxygen transport?

Answer 39

it remains constant, as the hemoglobin becomes 100% saturated and can't increase anymore regardless of increased Cardiac Output

Question 40

Why does HR decrease with training?

Answer 40

the muscles of the heart strengthen, allowing for greater force of contraction. Essentially, each beat can push more blood (an increase in stroke volume), therefore cardiac output can remain higher with lower heart rates

Question 41

name some causes of coronary occlusion:

Answer 41

- Deposition of cholesterol causing hardening and narrowing of the arteries - Fatty deposits also significantly reduce the diameter of the lumen - The restriction of blood flow increases pressure in the artery, leading to damage of the arterial wall - The damaged region is repaired with fibrous tissue which significantly reduces the elasticity of the wall - As the smooth lining of the artery is progressively degraded, lesions form called plaques, and if these rupture, blood clotting is triggered, forming a thrombus that restricts blood flow

Question 42

Risk factors for coronary heart disease

Answer 42

GODDESS acronym: Genetics obesitiy diet diseases exercise sex smoking