Transport in humans Flashcards
1
Q
Transport of materials in unicellular organisms
A
- unicellular organisms do not need a transport system for exchange or distribution of materials
- no part of cell is far from environment outside
- exchange of materials carried out easily thru diffusion
2
Q
Transport in multicellular organisms
A
- diffusion is inadequate of transport
- larger body, reduced SA:V
- cells located deeper in body, away from external environment
- transport system required
3
Q
What does blood contain?
A
- blood is a fluid tissue
- made up of plasma(55%), wbc, platelets, rbc
4
Q
Plasma
A
- 90% water, the following are dissolved and transported
- proteins eg. fibrinogen, prothrombin, antibodies
- mineral salts e.g. chlorides, sulfates of calcium, sodium
- food substances e.g. glucose, amino acids, fats
- waste products such as urea, uric acid, creatinine
- hormones e.g. insulin, glycogen
5
Q
Erythrocytes
A
- 99% cells in blood
- produced in bone marrow (ppl with leukemia need transplant)
- destroyed in spleen
- limited lifespan of 120 days (doesn’t have nucleus)
6
Q
Function of erythrocytes
A
-transport oxygen to cells in body
7
Q
Features of erythrocytes
A
- filled with red pigment called haemoglobin (essential for binding oxygen)
- absence of nucleus (more haemoglobin can be packed into cell)
- biconcave shape/enucleated, centre of cell thinner than edges (increase SA:V for efficient uptake of oxygen)
- elastic (enables cells to squeeze thru tiny capillaries)
8
Q
Leukocytes/ WBC
A
- larger than erythrocytes
- fewer
- produced in bone marrow
- destroyed in spleen
9
Q
Features of leukocytes
A
- limited lifespan of a few days although they have a nucleus (very highly involved in defense, nullify virus, pathogen, bacteria, toxin)
- colourless (no haemoglobin)
- irregular in shape (contain nucleus)
- mobile (they are able to move, change shape, squeeze thru walls of tiniest blood capillaries
10
Q
Types of leukocytes
A
- lymphocytes (highly specific)
- phagocytes (not specific)
11
Q
Lymphocytes
A
- large rounded nucleus
- small amt of non- granular cytoplasm
- produced specific antibodies against microorganisms
12
Q
Phagocytes
A
- lobed nucleus
- granular cytoplasm
- able to ingest foreign particles (like pacman)
- not specific
13
Q
Blood platelets/ Thrombocytes
A
- not true cells
- fragments of cytoplasm which are bound by membrane
- important for clotting blood
14
Q
Two things to check before operation
A
- haemoglobin level
- platelet count (need to heal fast)
15
Q
Antigens and antibodies
A
- plasma contains natural antibodies which recognize and bind to specific anitgens on the rbc
- rbc have proteins called antigens on their surfaces
16
Q
Blood type A
A
RBC: antigen A
Plasma: antibody b
Accept: A and O
17
Q
Blood type B
A
RBC: antigen B
Plasma: antibody a
Accept: B and O
18
Q
Blood type O
A
RBC: no antigens
Plasma: antibody a and b
Accept: O
19
Q
Blood type AB
A
RBC: antigens A and B
Plasma: no antibodies
Accept: all
20
Q
What happens if mix eg blood type A and B?
A
- antibody a in plasma of blood type B binds to antigen A in blood type A
- agglutination/clumping occurs
- antibodies act by binding
21
Q
Blood transfusion
A
- during blood transfusion, the effect of the recipient’s plasma on donor’s rbc is considered
- blood type O is the universal donor (no antigens so antibodies from recipient’s blood does not react with the rbc)
- blood type AB is the universal acceptor (no antibodies in plasma, no agglutination will occur)
22
Q
Functions of blood
A
- Transport (carry various substances from one part of body to another)
- Protective function (to protect body against disease-causing organisms)
- blood clotting or coagulation (prevent entry of bacteria into bloodstream or excessive blood loss)
23
Q
Transport function of blood
A
- blood acts as a transport medium carrying various substances
- digested food
- excretory products
- hormones
- heat
- oxygen
24
Q
Transport of oxygen to blood cells
A
- blood passes thru lungs, oxygen diffuses from alveoli and into blood
- haemoglobin binds with oxygen to form oxyhaemoglobin
- blood transports oxygen to all tissues in body
- at tissue cells, oxyhaemoglobin releases oxygen
25
Q
Acclimatization
A
- living in high altitudes, have increased no. of rbc
- increases amt of haemoglobin in blood
- more oxygen can be transported to body cells for aerobic respiration per unit time
26
Q
Protective function of blood
A
- blood clotting
- phagocytosis
- production of antibodies
27
Q
Clotting process
A
- blood clots when exposed to air
- this seals wound prevents entry of bacteria and excessive blood loss
- damaged platelets and tissues release the enzyme thrombokinase
- converts prothrombin to thrombin
- thrombin converts soluble fibrinogen to insoluble fibrin threads that entangles rbc to form blood clot
28
Q
Phagocytosis (pacman)
A
- process of engulfing and ingesting foreign particles e.g. bacteria by phagocytes (a type of wbc)
- phagocytes engulf foreign particles e.g. bacteria
- they are ingested and digested in the phagocyte
29
Q
Production of antibodies
A
- antibodies produced by lymphocytes (specific)
- bind to bacteria surface membrane, cos it to rupture and unable to control flow of substances, die
- bacterial cells clump together in presence of lymphocytes
- toxins produced by bacteria is neutralized by antibodies
30
Q
Organ transplant and tissue rejection
A
- involves replacing damaged or diseased tissue or organ with healthy ones from same person or donor
- recipient may produce antibodies to destroy the transplant
- ways to reduce risk of tissue rejection include a tissue match and use of immunosuppressive drugs (forces system to accept and adapt)
31
Q
Transport system in humans
A
- also known as cardiovascular system as it is made up of heart and blood vessels
- also known as circulatory system as it circulates blood arnd body
32
Q
At capillary bed
A
- arterial blood : oxygen and glucose
- venous blood: CO2, metabolic waste products (excretion is removal of CO2 or urea from body)
33
Q
Arteries
A
- transport oxygenated blood from heart to other organs
- have thick, muscular walls to support blood coming from heart which is higher in pressure (prevent slowdown of bloodflow)
- highly elastic (expansion when heart pumps)
- muscle contracts and relaxes to cause constriction and dilation of artery respectively
- constricts, narrower, less blood flow thru it per unit time
- dilate, lumen wider, more blood flow thru it per unit time
34
Q
veins
A
- relatively thin walls, less elastic tissue
- flow of blood is slower and bp lower compared to arteries
- have valves to prevent backflow of blood and muscle contraction helps to get blood from extremities
- valves are foldings of inner walls of veins
35
Q
Capillaries
A
- endothelium consists of a single layer of flattened cells, walls are partially permeable
- capillary network (branch repeatedly) increase surface area and total cross sectional area for more efficient exchange of substances between blood and cells
36
Q
Tissue fluid
A
- colourless fluid found in tiny spaces between cells
- useful materials e.g. oxygen and glucose move from blood in capillaries into tissue fluid and into cells via diffusion
- waste products released by cells move into tissue fluid by diffusion, thru capillary walls, into blood, carried to excretory organs for removal
37
Q
Double circulation
A
- blood moves thru heart twice as it moves from pulmonary circulation to systemic circulation
- blood enter pulmonary circulation at low pressure, sufficient time for blood to be fully oxygenated before returning to heart
- blood is pumped into systemic circulation at high pressure, blood quickly distributed to all tissues in body
38
Q
Coronary heart disease
A
- atherosclerosis is the buildup of fatty substances on inner surfaces of coronary arteries
- lumen of arteries narrowed, high pressure when blood tries to flow thru, might rupture, blood vessels damage, blood clot
- blood clot formed in artery (thromobosis)
- reduced blood flow to heart
- heart muscle cells receive reduced oxygen and nutrient supply
- region of heart muscle is damaged or dies, may lead to heart attack
39
Q
Causes of coronary heart disease
A
- high- fat diet rich in cholesterol and saturated animal fats
- emotional stress
- smoking
- sedentary lifestyle (makes fat deposits stay on arterial walls)
40
Q
Preventive measures
A
- healthy diet (reduce intake of animal fats, replace with polyunsaturated plant fats which do not stick to inner surface of arterial wall, lower cholesterol level. more veg and fruits)
- manage stress appropriately
- avoid smoking as nicotine and carbon monoxide increase risk of coronary heart disease
- exercise regularly (strengthens heart, maintains elasticity of arterial walls)
