Circulatory System Flashcards Preview

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Flashcards in Circulatory System Deck (27)
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1
Q

Name some of the features of the cardiac muscle which makes it suitable as a pump.

A
  • beats the whole human lifetime without rest.
  • incredibly high contrastive strength and endurance.
  • sends electrochemical signals so that all of the cells can contract together.
  • easily pump blood through the heart.
  • electrochemical signals are passed quickly.
  • set own contraction rhythm due to pacemaker.
2
Q

Explain the blood flow through the heart. (How it enters, where it goes, where it ends ect)

A
  • Deoxygenated blood travels through the superior vena cava and inferior vena cava.
  • blood goes into right atrium.
  • through the tricuspid valve and into the right ventricle.
  • goes up through the semilunar valve
  • through the pulmonary artery
  • TO THE LUNGS FOR GASEOUS EXCHANGE
  • the blood is then oxygenated
  • then sent through the bicuspid valve
  • through the left ventricle
  • out through the semi lunar valve
  • out the aorta
  • INTO THE BODY
3
Q

What is a “SA” node?

A

Sinoatrial node: principal pacemaker.

4
Q

What is a “AV” node?

A

Atrioventricular node: second pacemaker

5
Q

What do the Sinoatrial and Atrioventricular nodes in the heart do?

A

Send nerve impulses which initiate contraction of the heart.

6
Q

What is “Atrial Systole” ? And explain the process of this.

A

It is the atrium contracting.
Process:
- ventricles are in diastole.
- chordenae tendenee holds valves open therefore atrial contracts.
- SA node sends nerve impulse down left and right atria.
- atria contracts and forces blood into ventricles therefore tricuspid and bicuspid valves are open.

7
Q

What is “Ventricular Systole” ? And explain the process of this.

A

It is the ventricles contracting.

PROCESS:

  • AV node impulse travels down the septum to the apex.
  • impulse then travels upwards along Perkins fibres causing ventricles to contract in upwards motion.
  • pushes blood up in the aorta and pulmonary artery.
  • bicuspid and tricuspid prevent blood flow into atria.
  • semilunar valves open due to high blood pressure.
8
Q

What is “diastole” ? And explain the process of this.

A

It is the relaxing of the heart for an average of 0.4 seconds.
- at this time the heart if filling up with blood ready to pump it through again.

9
Q

Explain the process of the SA & AV nodes stimulating the heart.

A
  • AV node discharges its nerve impulse a fraction of a second after the SA node, therefore nerve impulse travels down the septum through the large bundles of fibre to the apex of the heart.
  • large bundles of fibres then divide into numerous ‘Perkins fibres’ which initiate the contraction of the ventricles.
10
Q

What is cardiac output?

A

The volume of blood pumped from one ventricle of the heart in one minute.

11
Q

What is stroke volume?

A

The volume of blood forced from a ventricle of the heart with each contraction.

12
Q

What is heart rate?

A

The number of times the heart beats per minute.

13
Q

What is venous return?

A

Rate of blood flow back to the heart.

14
Q

What is blood pressure?

A

The pressure of blood in the circulatory system.

15
Q

Explain some characteristics of arteries.

A
  • carries blood away from the heart.
  • blood pressure increases as ventricles contract.
  • blood flow decreases as the ventricles relax.
  • thick, muscular and elastic walls.
  • no valves.
16
Q

Explain some characteristics of veins.

A
  • carry blood away from the heart.
  • constant, relatively low blood pressure.
  • think, in elastic walls with little muscle.
  • often have valves.
17
Q

Explain some of the characteristics of capillaries.

A
  • microscopic blood vessel
  • links arterioles and ventricles
  • exchange of materials takes place here
  • permeable
  • substances pass through by diffusion
  • link arteries and veins
  • partly oxygenated
18
Q

What is pulmonic circulation? And explain the process.

A

The circuit of blood flow through the lungs where blood is oxygenated.
PROCESS:
- blood travels through the capillaries on the alveoli
- deoxygenated blood is taken to lungs and returns oxygenated

19
Q

What is systemic circulation? And explain the process.

A

The part of the blood circulation that carries oxygenated blood away from the heart, to the body and returns deoxygenated blood back to the heart.

20
Q

Name the components of blood.

With the percentage, appearance and function.

A

Plasma- 55% - liquid blood - the liquid that the cells are suspended in.

Erythrocytes- 45% - con caved sides, red/ pink in colour - carry haemoglobin around the body.

Leucocytes- 45% - blue/white in colour - remove dead or injured cells.

Thrombocytes- 45% - no nucleus, very small - “plug up” , make scabs, blood clotting.

21
Q

What is another name for Erythrocytes?

A

Red blood cells.

22
Q

What is another name for Leucocytes?

A

White blood cells.

23
Q

What is another name for thrombocytes?

A

Platelets.

24
Q

Explain the process of blood clotting.

A

1) chemical signal from damaged tissue activates thrombocytes which then become sticky.
2) Thrombocytes plug hole.
3) clotting factors in plasma produce fibrin which holds it all together like glue.
4) erythrocytes and Leucocytes become trapped in fibrin.
5) blood clot shrinks and retracts by pulling sides of vessel together, squeezes plasma out , forms protective barrier, then a scab.

25
Q

What is a lymph node?

A

Clumps of lymphoid tissues where lymph is filtered.

26
Q

What is the lymphatic system? And explain its role.

A

Network of vessels through which lymph drains from the tissues into the blood.

Role: bacteria and other microbes are picked up in the lymphatic fluid and trapped inside lymph nodes where they can be attacked and destroyed by the White blood cells.

27
Q

Explain the differences between the lymphatic system and the circularity system.

A

Circulatory system:

  • blood
  • blood is responsible for collecting and distributing nutrients and hormones to the tissues of the entire body.
  • blood flows in closed and continuous loops.
  • blood is pumped
  • blood consists of liquid plasma
  • blood is visible
  • blood is filtered by the kidneys
  • blood vessel damage or insufficiency produces swelling that contains low-protein fluid

Lymphatic system:

  • lymph
  • Lymph is responsible for collecting and removing waste products left behind in tissue
  • lymph flows in an open circuit from the tissues to the lymphatic vessels
  • lymph is not pumped it passively flows from tissues into capillaries
  • lymph that has been filtered, return to the cardiovascular system clear or a milky white fluid
  • lymph is invisible
  • Lymph is filtered by lymph nodes
  • lymphatic vessel damage or insufficiency produces swelling that contains protein rich fluid