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biology > topic 4.4 - circulation > Flashcards

topic 4.4 - circulation Flashcards

1
Q

structure of arteries

A
  • thick walls as they pump blood at high pressures
  • elastic fibres
  • small lumen
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2
Q

function of arteries

A
  • carry blood away from heart to cells in body (mostly oxygenated)
  • pulmonary artery is the exception where it carries de-oxygenated blood from the heart to lungs
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3
Q

what happens in peripheral arteries

A
  • the muscle fibres in cell wall either relax or contract to change the size of the lumen, controlling the blood flow
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4
Q

structure of capillaries

A
  • one cell thick
  • thin walls
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5
Q

function of capillaries

A
  • their structure allows capillaries to fit between individual cells
  • allows rapid diffusion of substances between the blood and the cells
  • O2 & other molecules diffuses out of blood and waste substances such as CO2 diffuses in
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6
Q

structure of veins

A
  • thin walls
  • large lumen
  • few elastic fibres
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7
Q

function of veins

A
  • carry blood back towards the heart - most carry de-oxygenated blood
  • pulmonary veins carry oxygenated blood from lungs to hearts
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8
Q

structure of the heart

A
  • four chambers - right and left atrium and ventricle
  • four main blood vessels - pulmonary vein, pulmonary artery, vena cava & aorta
  • atrioventricular valves - tricuspid/bicuspid
  • semi lunar valves - pulmonary/aortic
  • coronary arteries
  • cardiac muscle
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9
Q

function of :
- pulmonary vein
- vena cava (superior & inferior)
- aorta
- pulmonary artery
- cardiac muscle

A
  • pulmonary vein: from lungs to left atrium
  • vena cava: inferior deox blood from lower parts of body to heart and superior carries deox blood from upper part of body. Carried to right atrium
  • aorta: from left ventricle to body
  • pulmonary artery: right ventricle to lungs
  • cardiac muscle: thoicker on left hand side becuase high pressure is needed to pump blood to whole body
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10
Q

function of atrioventricular valves

A

prevent the back flow of blood

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11
Q

function of pulmonary/aortic valves

A

separate arteries from ventricles

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12
Q

function of coronary arteries

A

wrapped around the heart to supply blood to cardiac muscle of the heart

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13
Q

what is double circulation

A
  • involves two circulatory systems
  • systemic circulation carries oxygenated blood from the heart to the cells in the body and carries de oxygenated blood back to the heart
  • pulmonary circulation carries de oxygenated blood from heart to lungs where it is oxygenated and carries oxygenated blood back to heart
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14
Q

advantages of double circulation

A
  • concentration gradient is maintained as oxygenated & de-oxygenated blood don’t mix
  • blood pressure to body tissues is higher
  • blood pressure to lungs is lower (avoids damaging capillaries in lungs and increases time for gas exchange)
  • organisms can develop larger bodies
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15
Q

what is a single circulatory system (fish)

A
  • heart pumps de-oxygenated blood to gills and becomes oxygenated, giving up CO2 at the same time
  • blood travels around the rest of the body, giving up O2 to body cells before returning to the heart
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16
Q

stages of the cardiac cycle

A
  • atrial systole
  • ventricular systole
  • cardiac diastole
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17
Q
  1. atrial systole
A
  • the atria contract
  • this causes atrioventricular valves to open
  • blood flows into ventricles
18
Q
  1. ventricular systole
A
  • contraction of ventricles causes AV valves to close and semi-lunar valves open
  • hence blood leaves left ventricles through aorta and right ventricle through pulmonary artery
19
Q
  1. cardiac diastole
A
  • atria and ventricles relax
  • pressure inside heart chambers decreases
  • semi-lunar valves in aorta and pulmonary arteries close; preventing back flow of blood
20
Q

myogenic stimulation of the heart

A
  • the heart triggers its own beat so is said to be myogenic
21
Q

myogenic stimulation of the heart - how?

A
  • wall of right atrium contains SAN (aka pacemaker)
  • cells in SAN depolarise (become electrically excited)
  • electrical impulse is spread across the atria and atria contracts - atrial systole
  • impulses cannot pass directly down to the ventricles
  • between atria there is the AVN
  • AVN is connected to Purkyne fibres
  • AVN detects the electrical impulses passing over the atria
  • after a short delay AVN transmits electrical impulses down the Purkyne fibres
  • ventricles then contract
22
Q

why can impulses not be directly passed down to the?

A
  • because the ventricles are separated from the atria by a layer of non-conducting tissue
23
Q

Bundle of His

A
  • the Purkyne fibres bundled together are known as the Bundle of His
24
Q

what do the changes in electrical excitation of the heart cause and what are the changes measured with?

A
  • causes the repeating cardiac cycle
  • measured in an electrocardiogram (ECG)
25
Q

use of the electrocardiogram

A
  • 12 electrodes and leads are attached to the body
  • skin is wiped with alcohol to remove any sweat or grease so the electrodes make good contact
  • as recording is made, info is fed back from each of the electrodes giving 12 views of the heart
26
Q

what is tachycardia & bradychardia

A
  • tachycardia: fast heartbeat, many peaks with short gaps produced on the ECG
  • bradycardia: slow heartbeat, few peaks with long gaps produced on the ECG
27
Q
A
28
Q
A
29
Q

3 main functions of blood

A
  • transport hormones
  • defence
  • formation of tissue fluid & lymph
30
Q

components of blood

A
  • plasma
  • erythrocytes
  • leucocytes
  • platelets
31
Q

plasma - transporting & function

A
  • transport digested food products from small intestine to parts of body where they are needed
  • nutrient molecules from storage areas to cells that need them
  • excretory products from cells to organs
  • chemical messages from where they are made to cause changes in the body
  • maintains a steady body temp by transferring heat around the system
32
Q

erythrocytes - function & structure

A
  • contain haemoglobin
  • transport oxygen from lungs to all cells in the body
  • biconcave disc shape so large SA:V ratio so O2 diffuses in & out quickly
  • no nucleus so lots of space for haemoglobin to carry oxygen
33
Q

leucocytes - function & structure

A
  • much larger than erythrocytes
  • can change their shape
  • contain a nucleus and cytoplasm
  • defend body against infection
34
Q

types of granulocytes

A
  • have granules in cytoplasm of cells that take up stain and are pbvious under microscope
  • neutrophils
  • eosinophils
  • basophils
35
Q

type of agranulocytes

A
  • do not have granules to take up stain in cytoplasm
  • monocytes
  • lymphocytes
36
Q

neutrophils

A
  • part of non-specific immune system
  • engulf & digest pathogens by phagocytosis
  • multi-lobed nuclei
  • up to 70% of all leucocytes are nuetrophils
37
Q

eosinophils

A
  • part of non-specific immune system
  • stained red by eosin stain
  • important against parasites, in allergic reactions & in developing immunity to disease
38
Q

basophils

A
  • part of non- specific immune system
  • two lobed nucleus
  • produce histamines involved in inflammation and allergic reactions
39
Q

monocytes

A
  • part of specific immune response
  • largest leucocyte
  • can move out of blood into tissues to form macrophages
  • engulf pathogens by phagocytosis
40
Q

lymphocytes

A
  • small leucocytes with very large nuclei
  • vitally important in the specific immune response
41
Q

role of platelets in blood clotting

A
  • they form a plug and release clotting factors including thromboplastin
  • prothrombin changes to thrombin
  • soluble fibrinogen forms insoluble fibrin to cover the wound
42
Q

what is atherosclerosis

A
  • build up of plaque in the arteries
  • restricted blood flow

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