Term
| What is the shape of insect's hearts? |
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Definition
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Term
| Where is fluid pumped in insects? |
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Definition
| Pumped at low pressure along one main dorsal tube shaped heart |
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Term
| What is the fluid called? |
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Definition
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Term
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Definition
| Bathes the tissues directly, enabling gas exchange |
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Term
| What happens to haemolymph once the heart relaxes? |
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Definition
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Term
| Do insects have open or closed circulatory system? |
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Definition
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Term
| Do mammals and fish have closed or open circultory system? |
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Definition
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Term
| Explain the close circulatory system. (4 pts) |
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Definition
-Blood circulates in blood vessels
-Heart is a pump , pushing blood at high Pa
-Organs are not in direct contact with the blood but are bathed in tissue fluid
-Blood contains respiratory pigment |
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Term
| Explain the circulatory system of earthworms.(3 pts. Vessels,hearts,r.p) |
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Definition
-Have dorsal and ventral vessels running along the length of the body
-Connected by 5 pairs of pseudohearts
-Blood has a respiratory pigment |
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Term
Open and closed.
-Blood Pa
-Contact with organs
-Blood is contained in
-R.p.
-Transport of O2 |
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Definition
Open
*Low Pa-not in vessels
*Directly bathes tissues
*None
*O2 transported directly to tissues
Closed
*High Pa
*Blood in vessels so not in contact with organs
*In vessels
*Haemoglobin
*From lungs to heart and capillaries |
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Term
| What is single circulation? |
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Definition
| Blood passes through the heart once in one complete circulation. |
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Term
| What is double circulation? |
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Definition
| Blood passes through the heart twice in one complete circulation. |
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Term
| Give and explain the two circuits in double circulation. |
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Definition
Pulmonary- blood vessels that transport blood from heart to lungs
Systemic- blood vessels that transport blood from heart to tissues |
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Term
| Advantages of double circulation (3 points) |
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Definition
1. Maintains a high Pa in the systemic circulation- increases rate of flow to tissues so increased rate of O2 supplied to the tissues
2.Allows for a lower Pa in the pulmonary circulation - high Pa can cause tissue fluid build up in the lungs, damage blood vessels
3.Rapid circulation in the systemic circuit
Quick transport and removal of waste |
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Term
| Advantages of single ciculation |
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Definition
- b.p. less energy is needed to power the heart
- + Pa at the gills |
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Term
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Definition
| Transport blood away from the heart at high Pa |
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Term
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Definition
| Transport blood to the heart at low Pa |
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Term
| Definition of capillaries |
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Definition
Allow exchange of substances
with body cells |
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Term
| What is the endothelium and what is its function? |
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Definition
| One cell thick provides smooth lining which reduces friction and allows short diffusion pathway |
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Term
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Definition
Tunica media of veins and arteries
Strech and recoil to maintain a high b.p. |
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Term
| What is thick smooth muscle? |
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Definition
-Allows arteries to withstand high b.p.
-Contract and relax to direct blood flow to tissues |
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Term
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Definition
| Found in tunica externa, these are resistant to stretching |
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Term
| Why do veins have wide lumen? |
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Definition
| To deliver large volumes of blood back to the heart |
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Term
| Why do veins have thin walls? |
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Definition
| Low Pa due to further distance from the heart |
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Term
| Why do they have thin muscle layer? |
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Definition
| Allow contracting of skeletal muscle |
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Term
| What are and how do pocket valves work? |
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Definition
Ensure that blood flows in one direction.
-Blood above the valve tries to flow back
-Blood fills the pocket valves
-This forces the valves shut |
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Term
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Definition
| Able to adjust their diameter to vary the blood supply to a capillary bed |
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Term
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Definition
-One cell thick- short diffusion pathway and large cross-sectional area
-Permeable- allow sustances to dissolve and diffuse
-Narrow lumen-restricts blood flow slowing down the blood to allow more time for exchange of materials at the tissues. |
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Term
| What is the function of the tendinous cords? |
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Definition
| Prevent the valves inverting into the atria |
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Term
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Definition
| Largest artery and transports blood from the heart to the body |
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Term
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Definition
| Two veins that carry deoxygenated blood to the heart from upper and lower parts of the body |
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Term
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Definition
| Transport deoxygenated blood from the heart to the lungs where gas exchange takes place |
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Term
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Definition
| Transports oxygenated blood from lungs to the heart |
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Term
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Definition
| Supply the heart cells with oxygenated blood and glucose |
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Term
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Definition
| Remove deoxygenated blood from the cardiac muscle |
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Term
| Explain the blood flow through the heart and around the body. |
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Definition
-Oxygenated blood from lungs to the heart
-in the pulmonary vein
-Leaves the pulmonary vein and
-enters the left atrium
-It contracts and forces blood in left ventricle
-through the bicuspid valve
-Bicuspid valve closes , forcing blood up to the aorta through the SLV
-Oxygenated blood leaves the heart via the aorta to the tissues
-Deoxygenated blood from body in the vena cava
-Right atrium
-In the ventricle through the tricuspid valve
-Right ventricle through SLV
-Pulmonary artery and to the lungs |
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Term
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Definition
| Atria contract forcing the AVV open so blood flows in the ventrcles |
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Term
| What is ventricular systole? |
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Definition
Both ventricles contract forcing the blood in the arteries
AVV close and SLV open in the aorta and pulmonary artery |
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Term
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Definition
Atria and ventricle relax creating low Pa in the heart
SLV closed |
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Term
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Definition
| Volume of blood pumped form left ventricle per beat |
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Term
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Definition
| Pa of the blood in atria is + than Pa in the ventricles |
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Term
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Definition
| Pa in the ventricle is + than the aorta and pulmonary artery |
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Term
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Definition
| Arteries as they're closest to the heart, rhythmic rise and fall corresponding to ventricular contraction and relaxation |
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Term
| What is Pa in the arterioles? |
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Definition
| Depends on whether they are dilated or constricted |
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Term
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Definition
| Small diameter reduces Pa and fluid forced out also reduces blood flow and Pa in the capillaries |
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Term
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Definition
| Are too far awa from the heart to be affected by its contraction and relaxation, low Pa but not 0 bcz of the effect of the skeletal muscle |
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Term
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Definition
| the muscle generates its own contraction |
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Term
| Describe the control of heart beat. (6 points) |
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Definition
1. SAN acts as a pacemaker
2.Wave of depolarisation arises at the SAN and electrical causing the two atria to contract
3.Prevented from spreading to the ventricles by layer of connective tissue also acts as insulation
4.After short delay the impulse reaches AVN which passes the impulse to the ventricles
5.Impulse>>Bundle of his>>>Apex of the heart>>>Purkinje fibres>>>ventricular walls carry wave of depolarisation to the ventricle muscle
6.Impulse cause each ventricle to contract simultaneously from apex upwards, forces blood up and out. |
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Term
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Definition
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Term
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Definition
| Depolarisation of the atria during atrial systole |
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Term
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Definition
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Term
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Definition
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Term
| What does the length of the PR interval indicate? |
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Definition
| Time taken for the w.o.d. to spread from the atria to the ventricles |
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Term
| Why is QRS wave bigger than P wave? |
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Definition
| Ventricles have thicker muscular walls and so need more stimulation to contract |
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