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