Catégories : Tous - cells - antibodies - blood - oxygen

par Woon Kiat Il y a 14 années

491

Transport in Mammals

In mammals, the transport system is primarily facilitated by the blood, a complex fluid consisting of various components each serving critical functions. White blood cells, including lymphocytes and phagocytes, play a crucial role in the immune response by producing antibodies and ingesting foreign particles.

Transport in Mammals

Transport in Mammals

Blood

Platelets / Thrombocytes
Involve in clotting of blood

4. Fibrin threads entangle blood cells and the whole mass forms a clot

3. Soluble protein fibrinogen is then converted and catalysed by thrombin to form insoluble fibrin threads

2. Prothrombin, an inactive enzyme is then activated by thrombokinase and calcium ions to form thrombin

1. Damaged tissues and platelets produce thrombokinase, an active enzyme

Membrane-bound fragments of cytoplasm from certain bone marrow cells
Not true cells
White Blood Cells
Types

Phagocytes

Ingest foreign particles such as bacteria

a.k.a. Phagocytosis

Granular cytoplasm

Each has a lobed nucleus

Lymphocytes

Produce antibodies which protect that body from diseases

Small amount of non-granular cytoplasm

Each has a large rounded nucleus

Mobile
Contain nuclei
Irregular in shape
Absence of haemoglobin
Colourless
Red Blood Cells
Destroyed in the spleen

Releasing haemoglobin

Broken down in the liver

Forming bile pigments

Releasing iron which is then stored in the liver

Lifespan of 3 - 4 months
Produced by the bone marrow
Absence of nuclei
Flattened
Biconcave in shape

Increase surface area to volume ratio

Thus to allow the cells to absorb and release oxygen at a faster rate

Iron-containing protein
Contain the pigment haemoglobin

Enable them to transport oxygen from the lungs to all cells in the body

Combine reversibly with oxygen

Plasma
Hormones

Insulin

Excretory products

Carbon dioxide as hydrogencarbonate ions

Uric acid

Urea

Food substances

Fats

Vitamins

Amino acids

Glucose

Dissolved mineral salts
Soluble proteins

Antibodies

Help fight diseases

Prothrombin

Fibrinogen