Term
| State that coronary arteries supply... |
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Definition
| heart muscle with oxygen and nutrients. |
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Term
Explain the action of the heart in terms of collecting blood, pumping blood, and opening and closing of valves.
A. The Heart |
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Definition
| A: the heart: composed mainly of contractile muscle tissue, supported b connective, nerve, and epithelial tissues. |
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Term
Explain the action of the heart in terms of collecting blood, pumping blood, and opening and closing of valves.
B. Collecting of blood |
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Definition
- deoxgenated blood enters the right atrium from the inferior and superior vena cava
- oxygenated blood enters the left atrium from the pulmonary vein |
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Term
Explain the action of the heart in terms of collecting blood, pumping blood, and opening and closing of valves.
C. Pumping of blood |
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Definition
- contraction of the atria (right and left) pumps the blood into the ventricles (right and left)
- contraction of ventricles (right and left) pumps the blood into the pulmonary artery (right) and aorta (left) |
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Term
Explain the action of the heart in terms of collecting blood, pumping blood, and opening and closing of valves.
D. Opening and closing of valves |
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Definition
- as a function of pressure differences, one-way valves prevent backflow of blood
- atrioventricular valves prevent backflow from ventricles into atria
- semilunar valves prevent backflow of blood from pulmonary artery into right ventricle and from aorta into left ventricle |
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Term
Outline the control of the heartbeat in terms of myogenic muscle contraction, the role of the pacemaker, nerves, the medulla of the brain and epinephrine (adrenaline).
A. Heartbeat |
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Definition
| A. heartbeat: electrical impulses cause regular contractions of, first the two atria and then the two ventricles. |
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Term
Outline the control of the heartbeat in terms of myogenic muscle contraction, the role of the pacemaker, nerves, the medulla of the brain and epinephrine (adrenaline).
B. pacemaker and myogenic muscle contraction: |
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Definition
- the sino-atrial node (SAN), known as the pacemaker, is a specialised set of cells located on the right atrium
- SAN, not the brain, generates regular electrical impulses autonomously
- SAN impulses spread throughout both atria, causing simultaneous contraction
- impulses spread to ventricles only at the atrio-ventricular node (AVN) with a delay of about 0.1 seconds
- AVN transmits electrical signals to heart apex via bundles of His
- signals trigger powerful contractions of both ventricles from the apex towards the atria
- bundle of His transmits electrical signals throughout ventricles via Purkinje fibers, causing simultaneous contraction of ventricles |
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Term
Outline the control of the heartbeat in terms of myogenic muscle contraction, the role of the pacemaker, nerves, the medulla of the brain and epinephrine (adrenaline).
C. Nerve Stimulation |
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Definition
- sympathetic nerves from brain release epinephrine, increasing heart rate
- parasympathetic nerves from brain via vagus nerve decrease heart rate |
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Term
Outline the control of the heartbeat in terms of myogenic muscle contraction, the role of the pacemaker, nerves, the medulla of the brain and epinephrine (adrenaline).
D. Hormone Stimulation |
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Definition
| - adrenaline (epinephrine) from adrenal medulla increases heart rate |
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Term
Explain the relationship between the structure and function of arteries, capillaries and veins.
Artery |
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Definition
Vessel: Artery
Structure:
- inner endothelium
- thick walls of smooth muscle with elastic fibers
- outer layer of connective tissue with elastic fibers
Function:
- move blood away from heart under very high pressure (80-120 mm Hg) and high speed (10-40 cm/sec) |
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Term
Explain the relationship between the structure and function of arteries, capillaries and veins.
Vein |
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Definition
Vessel: Vein
Structure:
- inner endothelium
- thin walls of smooth muscle with elastic fiber
- outer layer of connective tissue with elastic fibers
-valves
Function:
- move blood toward heart under very low pressure (10 mm Hg) and moderate speed (5-20 cm/sec)
- prevent backflow of blood |
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Term
Explain the relationship between the structure and function of arteries, capillaries and veins.
Capillary |
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Definition
Vessel: Capillary
Structure:
- thin single layer of endothelium
- surrounded by basement membrane
- numerous
Function:
- Allow diffusion of dissolved materials between blood & tissues
- under low pressure (20-40 mm Hg) and low speed (<1 cm/sec) |
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Term
| State that blood is composed of... |
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Definition
plasma, erythrocytes, leucocytes (phagocytes and lymphocytes), and platelets.
- Plasma (serum) 54-57%
- Proteins make up 6-8% of the plasma
- Red cells 42-45%
- White cells and platelets 0.2-0.5% |
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Term
| State that the following are transported by the blood: |
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Definition
| nutrients, oxygen, carbon dioxide, hormones, antibodies, urea and heat. |
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