Circulatory systems

Question 1

What distance can diffusion play an important role in substance exchange?

Answer 1

<100um

Question 2

What is the rate of diffusion?

Answer 2

Fick’s law: Rate of diffusion α surface area x concentration difference

(divided by) thickness of membrane

Question 3

What is an open circulatory system?

Answer 3

Where circulatory fluid does not return to the heart. In anthropods the hemolymph, which bathes body cells and organs, in sinuses exits through pores throughout the body

Question 4

Capillary beds are the sites of exchange for which networks?

Answer 4

blood and interstitial

Question 5

What blood vessel converges into veins?

Answer 5

Venules

Question 6

Bony fish have how many ventricles?

Answer 6

1

Question 7

Fish have a low metabolic rate because they are..

Answer 7

ectothermic

Question 8

What 2 circuits do amphibians possess?

Answer 8

The systemic circuit and the pulmocutaneous circuit

Question 9

Amphibians have a ___ dividing the atrium

Answer 9

ridge (not septum)

Question 10

Mammals and birds require more O2 because they are _____

Answer 10

endotherms

Question 11

What is the diastole phase of the cardiac cycle?

Answer 11

the relaxation, filling phase

Question 12

What is the systole phase of the cardiac cycle?

Answer 12

The contraction or pumping phase

Question 13

Where is the pulmonary valve?

Answer 13

In the pulmonary artery leading away from the right ventricle

Question 14

What is the name of the valve leaving the right atrium into the right ventricle?

Answer 14

Tricuspid valve

Question 15

What is the name of the valve in the aorta

Answer 15

Aortic valve

Question 16

What is the name of the valve leaving the left atrium into the left ventricle

Answer 16

Mitral valve

Question 17

Which valves are atrioventricular valves?

Answer 17

Tricuspid and mitral. They attach to tendinous cords

Question 18

Which valves are semilunar valves?

Answer 18

Aortic and pulmonary. Operates due pressure preventing backflow

Question 19

What does autorhythmic mean? (in regards to muscle cells)

Answer 19

contract repeatedly without any signal from the nervous system

Question 20

Where is the SA node located?

Answer 20

in the right atrium

Question 21

STEP ONE OF HEART CONDUCTION SYSTEM

Answer 21

Both atria contract in unison

Question 22

STEP TWO OF HEART CONDUCTION SYSTEM

Answer 22

The AV node relays electrical impulses.. delaying for 0.1 secs to allow for atria to drain

Question 23

STEP THREE OF HEART CONDUCTION SYSTEM

Answer 23

Bundle branches pass signals to heart apex.

Question 24

STEP FOUR OF HEART CONDUCTION SYSTEM

Answer 24

signals spread throughout ventricles contracting upwards

Question 25

What effect does epinephrine have on the SA node?

Answer 25

Speeds up SA node

Question 26

Which system controls heart rate?

Answer 26

The autonomic nervous system, sympathetic and parasympathetic

Question 27

Which T levels of spinal cord does the sympathetic nerves that release norepinephrine which acts on entire heart do they originate from?

Answer 27

T1-T4, increases heart rate and force of contraction

Question 28

Where do the parasympathetic nerves originate from that mostly act on SA node?

Answer 28

Vagus nerves, release acetylcholine which decreases heart rate and force of contraction.

Question 29

What is stroke volume?

Answer 29

Amount of blood pumped in a single contraction

Question 30

What blood vessel type contains valves?

Answer 30

Veins

Question 31

What are two qualities of arteries?

Answer 31

To act as a pressure reservoir for forcing blood into small diameter capillaries To dampen oscillations in pressure and flow generated in the heart

Question 32

Which blood vessel type acts as a storage reservoir?

Answer 32

Veins

Question 33

How is blood returned to the heart from veins considering how low the pressure is?

Answer 33

One-way valves Skeletal muscle contraction

Question 34

What is Deep Vein Thrombosis (DVT)?

Answer 34

Pooling of blood in deep veins leading to a clot formation

Question 35

How do you calculate pulse pressure?

Answer 35

Systole - diastole

Question 36

Why does velocity increase again after entering capillaries unlike pressure?

Answer 36

Pooling back into bigger blood vessels

Question 37

How do things move in and out of capillaries?

Answer 37

Actively by bulk flow through intercellular spaces between endothelial cells

Question 38

What are the tight junctions in the capillaries?

Answer 38

lose intercellular spaces forming the blood-brain barrier Require a greater number of mitochondria

Question 39

How is fluid exchanged in the capillaries?

Answer 39

thin capillary endothelial cell wall Blood pressure tends to drive fluid out of capillaries Blood proteins, creating osmotic pressure, tends to pull fluid back into capillaries On average there is a net loss of fluid from capillaries

Question 40

What is the net pressure of fluid exchange in the arterial end?

Answer 40

(32mmHg - 22mmHg) 10mmHg .. fluid flows out

Question 41

What is the net pressure of fluid exchange in the venous end? (think blood pressure dropping)

Answer 41

15 - 22 = -7mmHg , fluid flows in

Question 42

What is the net fluid exchange overall?

Answer 42

(10 - 7) 3 mmHg

Question 43

What happens to the overall net fluid?

Answer 43

The lymphatic system returns fluid that leaks out from capillary beds.. fluid lost is lymph. Drains into veins in the neck. Valves in lymph vessels prevent backflow

Question 44

What is oedema?

Answer 44

Swelling caused by disruptions in the flow of lymph

Question 45

What is the pleural membrane, space/cavity and fluid?

Answer 45

Parietal and visceral layers/pleura Potential space between these layers containing fluid Fluid prevents friction, causes layers of pleural membrane to adhere to one another (surface tension)

Question 46

What kind of epithelium make up the alveoli

Answer 46

Simple squamous

Question 47

What makes up the respiratory membrane?

Answer 47

Fluid with surfactant lining the alveolus reduces surface tension & allows alveolar expansion when breathing in. Alveolar epithelium Interstitial space Capillary endothelium -Diffusion distance is 0.2-0.6μm (short)

Question 48

Is the pressure negative or positive when breathing in?

Answer 48

negative

Question 49

How is breathing controlled?

Answer 49

Regulated by blood pH (~7.4). If pH falls (due to rising CO2 levels) sensors in the aorta and carotid arteries at the same time as the medulla detects pH in cerebrospinal fluid. The medulla signals for increased breathing.

Question 50

What is haemoglobin?

Answer 50

A protein containing four subunits each consisting of a polypeptide chain & a haem group Each haem group contains an iron atom to which an oxygen molecule can bind

Question 51

What are the main values of partial pressure needed for oxygen transport?

Answer 51

Air is 160 mmHg Lungs are 100mmHg Tissue: 40mmHg at rest and <20 mmHg during exercise Venous blood is 40 mmHg Arterial blood is 95mmHg

Question 52

What is the haemoglobin dissociation curve displaying?

Answer 52

There is co-operativity between the haem subunits Thus when one subunit unloads O2 the others then more readily unload This is because changes in their shape decrease their affinity

Question 53

How is CO2 transported in the blood

Answer 53

90% as: CO2 + H2O = H2CO3 (carbonic acid) catalysed by carbonic anhydrase within red blood cells H2CO3 = H+ + HCO3- (bicarbonate)