Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biomedicine I > 6. Cardiovascular System II > Flashcards

6. Cardiovascular System II Flashcards

1
Q

Circulation

A

Systemic Circulation Pulmonary Circulation

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

Systemic Circulation

A

• Blood from the heart is distributed around the bodybefore returning to the heart.

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

Pulomonary Circulation

A

• Blood from the heart to the lungs and back to the heart.

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

Blood Vessels

A

• The three main types of blood vessels are arteries, veins and capillaries. • Smaller arteries are called ‘arterioles, whilst smaller veins are called ‘venules’. • Capillaries are small blood vessels connecting arterioles & venules. • Capillaries specialise in the exchange of substances between blood & cells/tissues.

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

Arteries/arterioles

A

Location: Carries blood away from the heart Blood content: Oxygenated (exceptions: pulmonary & umbilical arteries). Pressure: High

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Veins/venules

A

Location: Carries blood towards the heart Blood content: Deoxygenated (exceptions: pulmonary & umbilical veins). Pressure: Low

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

Blood Vessel Structure

A
  1. Tunica Externa 2. Tunica Media 3. Tunica Intima • The thickness (& presence) of each layer depends on the type of blood vessel… • Arteries and arterioles have a thicker tunica media and are hence more muscular. • Veins and venules generally have thin walls. The tunica externa is their thickest layer. • Capillariescontain only an endothelium.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Tunica Externa

A

Outermost layer made of elastic & collagen fibres. Contains nerves and small blood vessels that supply the walls of large blood vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Tunica Media

A

Layer of smooth muscle that controls blood vessel diameter.

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

Tunica Intima

A

The innermost layer made of endothelium. Contains epithelium to protect the vessel wall and functions to secrete chemicals. This layer is in direct contact with blood and is well positioned to monitor and respond to changes.

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

Blood Vessel Structure: Arteries

A

• Large portions of elastic tissue (high pressure). • Sympathetic nerve fibres innervate smooth muscle and cause vasoconstriction. • If reduced sympathetic activity, ‘Nitric Oxide’ is released which causes vasodilation.

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

Blood Vessel Structure: Arterioles

A

•Arterioles are small arteries and are vital in maintaining blood pressure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Blood Vessel Structure: Veins

A

•Skeletal muscle contraction aids return of venous blood to the heart. •The pumping action of heart is major drive. The respiratory pump also aids return (diaphragm). •Veins contain valves.

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

Capillaries

A

• Capillaries contain only one layer of cells (the ‘endothelium’). • Capillaries function in the exchange of substances between blood and cells. • Found near every cell in the body. • Tissues with high metabolic demand have extensive capillary network. • The structure of capillaries allows easier passing of substances between the blood and cells/tissue (H2O, O2, CO2& other nutrients / wastes).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Capillary Exchange

A

• The key function of the cardiovascular system is to keep blood flowing through capillaries to allow exchange. • Water–by osmosis • Nutrients –by facilitated diffusion & active transport. • Gases –Carbon dioxide and oxygen by diffusion down gradient.

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

Where is your Blood?

A

64% blood in systemic veins/venules. 13% in systemic arteries/arterioles. 9% in pulmonary vessels. 7% in capillaries. 7% in heart.

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

Portal Circulation

A

• Venous blood passes from the digestive tract, spleen & pancreas directly to the liver. • This system of blood flow is known as the ‘hepatic first pass’. • The vessel that carries the absorbed substances is called the ‘portal vein’.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Vasodilation and Vasconstriction

A

• All blood vessels (except capillaries) have smooth muscles which are influenced by the autonomic nervous system: • Sympathetic nervous system stimulation causes vasoconstriction. • The parasympathetic nervous system has little influence.

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

Vasodilation

A

Reduces blood pressure.

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

Vasoconstriction

A

Increases blood pressure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

The Heart

A

• The heart is a fist-sized muscular organ that functions to pump blood around the body. • Beats 100,000 times each day. • In a life-time will beat 2.5 billion times. • The heart contracts to pump blood through blood vessels. • Blood pumps through 60,000 miles of blood vessels within the human body. • The heart is approximately 12cm long and 9cm wide. • Average Mass: 250g in females. 300g in males.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Heart: Location

A

• The heart rests on the diaphragm, near the midline of thoracic cavity, pointing left. • In the thoracic cavity (‘mediastinum’). • The heart is covered anteriorly by the sternum and ribs 3-6. • Apex of the heart is formed by the left ventricle and lies in the 5th intercostal space.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Heart Layers

A

Pericardium Myocardium Endocardium

24
Q

Pericardium

A

•Outer layer of the heart. •Thin double-layeredmembrane:contains a fibrous pericardium that attaches to the diaphragm and an inner serous pericardium that consists of a visceral and parietal layer. •Functions to keep the heart in position within the thorax & allow free movement during contractions.

25
Q

Myocardium

A

• Middle layer. • The thickest layer of the heart wall is the myocardium – making up 95% of the heart. • The myocardium is formed of cardiac muscle. • Cardiac muscle is striated & involuntary. • A unique property of cardiac muscle is its ability to generate its own rhythm of contraction (cardiac muscle is ‘autorhythmic’). • As the myocardium is so metabolically active (always contracting), the arterial supply is vital. The ‘coronary artery’ delivers oxygenated blood to the myocardium. • Functions to pump blood out of the heart

26
Q

Endocardium

A

• Innermost layer. • Thin layer of endothelium overlying a thin layer of connective tissue. • Provides a smooth lining for the heart chambers (also covers heart valves).

27
Q

The Heart Chambers

A
  1. Right atrium. 2. Right ventricle. 3. Left atrium. 4. Left ventricle.
28
Q

Flow of blood

A

• The atria are the receiving chambersof the heart (receive venous blood). • The atria pump blood into the ventricles. • The atria are separated by the interatrial septum, whilst the ventricles are separated by the interventricular septum.

29
Q

Right Atrium

A

3mm thick Receives deoxygenated blood from superior & inferior vena cava. Pumps blood into the right ventricle throughthe tricuspid valve.

30
Q

Right Ventricle

A

5mm thick Receives deoxygenatedblood from right atrium. Pumps blood to the lungs through the pulmonary valve into the pulmonary trunk which divides into left and right pulmonary arteries.

31
Q

Left Atrium

A

3mm thick Receives oxygenated blood from lungs via the pulmonary vein Pumpsblood to the left ventricle through the mitral/bicuspid valve.

32
Q

Left Ventricle

A
  • 10-15mm thick
  • Receives oxygenated blood from the left atrium
  • Pumps blood through the aortic valve into the ascending aorta.Some of the blood in the aorta flows into the coronary arterieswhich carry blood to the heart wall
33
Q

The Heart

A

A. Tricuspid valve

B. Pulmonary valve

c. Bicuspid/Mitral Valve
d. Aortic valve
e. Right Atrium
f. Right Ventricle
g. Left Atrium
h. Left Ventricle
i. Inferior Vena Cava
j. Superior Vena Cava
k. Pulmonary Artery
l. Pulmonary Vein

34
Q

Foramen Ovale

A
  • Within the interatrial septum is a depression called the ‘fossa ovalis’.
  • Previously called the ‘foramen ovale’in foetal development, where it would shunt blood from the right atrium to left atrium, to bypass the lungs.
35
Q

Ductus arteriosum

A
  • During foetal life (8 weeks+), a temporary blood vessel called the ductus arteriosum shunts blood from the pulmonary trunk to the aorta.
  • Closes after birth to form ligamentum arteriosum.
36
Q

Heart Contraction

A
  • The myocardium performs periodic contractions through a network of cardiac fibres that are self excitable (‘autorhythmic’).
  • The myocardium repeatedly generates nerve impulses.
  • Hormones, age, sex, body position, exercise, stress and temperature all influence heart rate and strength.
37
Q

Conduction System of the Heart

A
  1. Sinoatrial node (SA node)
  2. Atrioventricular node (AV node)
  3. Atrioventricular bundle (bundle of his)
  4. Right and Left bundle branches
  5. Purkinje fibres
38
Q

Conductive System

A
  1. Sinoatrial Node
  2. Atrioventricular Node
  3. Atrioventricular Bundle (Bundle of His)
  4. Right and Left Bundlle Branches
  5. Purkinjes Fibres
39
Q

Sinoatrial Node (SA Node)

A
  • The SA node is the ‘pacemaker’ of the heart –sets rate & rhythm.
  • Initiates cardiac conduction, located in the right atrial wall.
  • Each action potential from the SA node propagates through each atria via gap junctions, causing atrial contraction.
40
Q

Atrioventricular node (AV node)

A
  • A ‘relay station’ –conduct impulses at a slightly slower rate to allow the atria to finish contracting.
  • Located in the bottom right of the interatrial septum.
41
Q

Atrioventricular bundle (bundle of his)

A

• Only site where action potential can conduct from atria to ventricles.

42
Q

Right and Left bundle branches

A

• From the bundle of his, the action potential enters the left and right bundle branches, which extend the interventricular septum towards the apex of the heart.

43
Q

Purkinje Fibres

A

• Finally the purkinje fibres rapidly conduct the action potential beginning at the apex of the heart, up the remainder of the ventricular myocardium causingventricular contraction.

44
Q

Myocardial Metabolism

A
  • Despite the heart accounting for only 1% of the total body weight, the myocardium consumes 10% of the total body oxygen consumption.
  • Cardiac muscle is an aerobic organ with a limited capacity to work under oxygen debt.
  • Therefore, poor oxygen delivery to the myocardium could cause cell death (necrosis).
  • Fatty acidsare the predominant fuel in cardiac muscle (50-70%), followed by glucose(30%).
  • During exercise, the heart can use lactic acid to produce ATP.
45
Q

Electrocardiogram

A

• As action potentials propagate through the heart, they generate electrical currents that can be detected on the surface of the body.
• An ECG amplifies these electrical signals.
 P wave –represents atrial depolarisation (from SA node)
 QRS wave –represents rapid ventricular depolarisation (hence sharp curve).
 T wave –ventricular repolarisation (resting).

46
Q

Pulse Rate

A

• The pulse is a blood pressure wave originating from the heart.
• Varies depending on the stage of life.
Pulse rate (based on age):
• New-born -130
• 3 months -140
• 6 months -130
• 1 year -120
• 2 years -115
• 3 years –100
• 4 to 6 years -100
• 8 years -90
• 12 years -85
• Adult -70 to 90 (average)

47
Q

Cardiac Output

A
  • Cardiac output is the volume of blood being pumped out by the heart per minute.
  • The stroke volume = volume ejected per beat from both ventricles.
  • Cardiac Output = stroke volume x heart rate (average = 5 L/min).
48
Q

Systole

A

The force that drives blood out of the heart(contraction)

49
Q

Diastole

A

Period of relaxationwhen the heart fills with blood

50
Q

Tachycardia

A

resting heart rate over 100 bpm

51
Q

Bradycardia

A

resting heart rate under 60bpm

52
Q

Blood Pressure

A
  • The pressure exerted by circulating blood on the blood vessel walls.
  • Constitutes one of the principal vital signs.
  • The pressure progressively decreases away from the heart through arteries and then back toward the heart through veins.
  • Normal ranges (NHS) = 90/60-140/90mmHg. However this varies patient to patient and ranges differ between countries.
  • Vasoconstriction increases blood pressure.
  • Vasodilation lowers blood pressure.
  • Highest priority for blood supply is to the brain & heart.
53
Q

Cholesterol

A
  • Cholesterol is a vital compound for cell structure and function. It is in every body cell.
  • Some of the key functions of cholesterol include:
    • Cell membrane integrity (vital in the brain).
    • Vitamin D and calcium metabolism.
    • Sex hormones (e.g. oestrogen, testosterone).
  • Cholesterol is acquired from liver cells (hepato-cytesproduce 1000mg daily) and from diet.
  • Cholesterol is vital, but in excess is thought to be part of the pathogenesis of arterial plaque formation.
  • As cholesterol is hydrophobic it needs to be transported around the body –transported as lipoproteins. (HDL and LDL)
54
Q

Lipoproteins

A

Low density lipoproteins (LDL):
• Carry 75% total cholesterol in blood, carrying it from the liver to cells of the body.
• When present in excess LDLs can deposit cholesterol in arteries.
High density lipoproteins (HDL):
• Remove excess cholesterol from body cells and blood and transport it to the liver.
• Prevent accumulation of cholesterol in blood.

NHS Cholesterol Guidelines:
• 5mmol/L or less for healthy adults and 4mmol/L or less for those at high risk.

55
Q

Cardiovascular System: Homeostasis

A

The heart and blood vessels service the whole body, delivering nutrients, removing waste & distributing heat.
Skin:
• Blood delivers clotting factors and white blood cells to aid repair when the skin is injured.
• Changes in blood flow to the skin is used to adjust body temperature.
Skeletal system:
• Blood delivers bone minerals & hormones to control bone remodelling and RBC production (erythropoietin) to the bone.
Muscular system:
• Blood transports heat and lactic acid from the muscles.

Endocrine system:
• Blood delivers hormonesto their target tissues.
Lymphatic/Immune system:
• Blood distributes immune cells around the body.
Respiratory system:
• Blood transports substances such as oxygenand carbon dioxide.
Digestive system:
• Blood carries absorbed nutrients to the liver.
• Blood distributes hormones that aid digestion.
Urinary system:
• 20% of the cardiac output goes to the kidneys for filtering.
Reproductive system:
• Blood distributes reproductive hormones.

56
Q
A

Biomedicine I (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions