Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Structure and function of living organisms > Circulatory systems > Flashcards

Circulatory systems Flashcards

(50 cards)

Start Studying
1
Q

What are the functions of a circulatory system?

A
  • distribution of nutrients, water and electrolytes
  • support for metabolism
  • transportation of hormones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the principle components of a circulatory system?

A
  • fluid that circulates through the system
  • a propulsive mechanism that drives fluid
  • system of tubes or channels through which fluid flows
  • one way valves or septa that ensure unidirectional flow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the features of an open circulation?

A
  • incomplete set of vessels
  • circulating fluid known as haemolymph
  • haemolymph freely percolates through intercellular spaces
  • heart may propel haemolymph through vessels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the features of a closed circulation?

A
  • complete and continuous system of blood vessels
  • fluid id blood
  • heart propels blood through vessels
  • intercellular spaces filled with interstitial fluid
  • lymph in lymphatic vessels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the requirements for an efficient circulatory system?

A
  • efficient oxygen carriers in blood or haemolymph
  • efficient gas exchange
  • efficient delivery of nutrients and oxygen
  • efficient gas exchange in tissues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Write an equation for flow rate

A

flow rate = change in pressure/ resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the difference in pressure in closed circulatory systems and open circulatory systems?

A

closed: change in P is high and R is low
open: change in P is low and R is low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the arrangement of the mammalian cardiovascular system

A
  • four-chambered heart (unidirectional flow)
  • blood supplies to systemic vascular beds run in parallel
  • pulmonary circulation runs in series
  • high-pressure system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Write an equation for cardiac output

A

cardiac output (L/min) = Heart Rate (beats/min) x Stroke Volume (L/beat)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

List the sections of an ECG waveform in order

A

P, Q, R, S, T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which processes relate to each section of the ECG waveform?

A

P wave - depolarisation of atria
PR interval - conduction through AV node
QRS complex - depolarisation of ventricles
QT duration - ventricular depolarisation and repolarisation
T wave - repolarisation of ventricles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe how stimulation regulates the heart rate

A
  • parasympathetic stimulation slows HR
  • sympathetic/adrenergic stimulation accelerates HR
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the 2 phases of the cardiac cycle?

A

systole - contraction of chamber and ejection of blood
diastole - relaxation and filling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

List the events of the cardiac cycle

A
  1. atrial systole
  2. isovolumeric contraction of the ventricles
  3. ventricular ejection
  4. isovolumeric relaxation of the ventricles
  5. passive ventricular refilling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is stroke volume modified by?

A

intrinsic control - degree of stretch of cardiac muscle (starling’s law)
extrinsic control - sympathetic stimulation (modulation of Ca availability)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is starling’s law?

A

states that the more the heart chambers fill, the stronger the ventricular contraction - leads to greater stroke volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe the location the heart

A
  • posterior to the sternum
  • within the mediastinum of the thorax between the left and right lungs
  • orientated with the apex pointing to the left
  • superior to diaphragm
  • great vessels enter and leave heart at superior aspect
  • protected by several layers of pericardium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the function of the coronary artery?

A

provides oxygen rich blood to the myocardium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the predominant cause of myocardial infarction?

A

thrombi (clots) with the left anterior descending artery being a common site of blockage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Where does the right atrium receive blood from?

A
  • the head, neck , thorax and upper limbs via superior vena cava
  • blood from coronary circulation enters via coronary sinus
  • the trunk, pelvis and lower limbs via inferior vena cava
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the function of the sino-atrial node?

Study These Flashcards
A

responsible for generating electrical activity to stimulate contraction

22
Q

What is the fossa ovalis?

Study These Flashcards
A

the remnant of a hole (foremen ovale) in the inter-atrial septum during foetal development

23
Q

What is the tricuspid valve?

Study These Flashcards
A

an atrioventricular valve located between the right atrium and right ventricle

24
Q

What is the pulmonary valve?

Study These Flashcards
A

a semilunar valve located between the right ventricle and the pulmonary trunk

25
What is the bicuspid valve?
an atrioventricular valve located between the left atrium and left ventricle
26
What is the aortic valve?
a semilunar valve located between the left ventricle and the aorta
27
What are the chordae tendinae?
extend from papillary muscles to the leaflets of the two AV valves and prevent backflow of blood during systole
28
List the three layers of the heart
endocardium - lining myocardium - muscle layer epicardium - visceral pericardium
29
Describe how valves are pulled shut during systole
- atrial depolarisation - conduction down bundle of His and purkinje fibres - ventricular depolarisation - paillary muscles depolarise and contract - chordae tendinae pulled under tension - atrioventricular valves pulled shut despite high pressure in ventricle - blood cannot backflow into aorta - blood ejected through open semilunar valves
30
List the three types of cell-cell junctions that link the heart muscle cells at intercalated discs
1. adherens junction - link actin cytoskeleton to allow sarcomere contraction 2. demosomes - link intermediate filaments to provide strength 3. gap junctions - link cytosol to allow cell-cell communication, coordination of contraction from cell to cell along heart muscle fibres
31
List the vascular arteries
- common carotid artery - abdominal artery - femoral artery - subclavian artery - brachial artery - radial artery
32
Lis the 3 components of blood vessels
1. tunica intima --> endothelial plus connective tissue (basement membrane) 2. tunica media --> smooth muscle cells and connective tissue, bordered by inner boundary (internal elastic lamina) and outer boundary (external elastic lamina) 3. Tunica adventitia --> connective tissue
33
What makes the aorta and pulmonary tank specialised?
- wide lumen - thick walls with a thick tunica media - large amounts of elastic fibres (stretch and recoil) and collagen (prevent overexpansion) - incorporate vasa vasorum into their tunica adventitia to provide oxygen to the smooth muscle cells in the vessel
34
What makes muscular ateries specialised?
- feature a thick tunica media of smooth muscle (manage high arterial pressure) - smooth muscle cells orientated in a circular not longitudinal direction
35
What are sinusoids?
- specialised, widened capillaries that can permit a greater passage of erythrocytes - found in bone marrow, spleen, lymph nodes and liver
36
What is the function of venules?
permit the exit of deoxygenated blood from capillary beds
37
What regulates substances into and out of the brain?
the blood brain barrier (interface between blood and tissues of the brain parenchyma)
38
List the features of the blood brain barrier
- a strong endothelium - specialised tight junctions between endothelial cells - presence of additional cell barriers including astrocytes and pericytes
39
Describe the tunica intima
- endothelium lines the entire cardiovascular system - regulates passage of substrates in and out of the blood by permitting transfer between vessels and their surroundings - endothelial cells provide a minimal barrier from one side to the other - tissue fluid is exchanged across the endothelium
40
What is the role of the tight junction?
important in sealing the paracellular space between two adjacent endothelial cells
41
Describe the tunica media
- smooth muscle cells are spindle-shaped have a circular arrangement, wrapping around the vessel
42
List the two components of blood or haemolymph pressure
- dynamic pressure produced by the pump - hydrostatic pressure of the fluid
43
Which factors affect flow rate?
- fluid viscosity - vessel length - vessel radius
44
Calculate the total resistance in series
Rtot = R1 + R2 + R3....
45
Calculate the total resistance in parallel
1/Rtot = 1/R1 + 1/R2 + 1/R3 .....
46
What are the functions of arteries?
- conduit for capillary beds - acts as pressure reservoir to drive blood into arterioles - damp oscillations in pressure and flow - control differential distribution to different organs and tissue
46
What are the functions of veins?
- conduit for blood to return to heart - act as blood reservoir - flow influenced by external factors
47
What can affect smooth muscle tone?
- neurotransmitters - hormones - endothelium-derived substances - metabolites and related factors - other locally-produced factors - other factors
48
What is total fluid energy?
- potential energy acquired from the beating of the heart - kinetic energy of the fluid itself - potential energy of the fluid that it possesses because of its position in the gravitational field
49
Describe the effects of gravity on fluid energy
- above the heart, arterial pressure decreases with height - below the heart, fluid-column effects increase the arterial pressure

Structure and function of living organisms (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions