TRANSPORT IN HUMANS

Coronary Heart disease

When the heart muscle cells are deprived of oxygen and glucose and poisonous wastes such as lactic acid buildup.

Part of the heart muscle stops contracting, causing a heart attack

Caused by:
Stress
Smoking
Poor Diet
Poor Lifestyle
Genetics

Prevented by:
Not smoking
Avoiding fatty food
Exercising regularly

Treated by aspirin and surgery (stents, angioplasty, or by-pass)

Blood Vessels

Capillary: allow substances to diffuse into cells

Vein: transports low pressure blood to the heart

Arteries: transport high pressure blood from the heart

Elastic walls to expand and relax (causing a pulse)

Thick walls to withstand pressure

Rings of muscle narrow or widen to control blood flow

Valves prevent backflow of blood

Blood is at low pressure, but nearby muscles squeeze veins and help push blood to the heart

Large diameter and thin walls to reduce resistance to flow of blood

One cell thick for easy diffusion

Highly branched, large surface area

Capillary beds constantly supplied with fresh blood so diffusion occurs

Heartbeat

Electrical activity can be monitored by:
-an electrocardiogram
-pulse rate
-listening to the sounds of valves closing

Physical activity makes the heart beat more quickly and more deeply, for an increased circulation of blood so that more oxygen and glucose can get to the muscle quickly

Blood

Red blood cells: haemoglobin and oxygen transport

White blood cells: phagocytosis and antibody formation

Platelets: cause clotting

Plasma: transports blood cells, ions, soluble minerals, hormones, carbon dioxides, urea, plasma proteins

Clotting #

Reduces blood loss and keep pathogens out!

Fibronogen turns to fibrin and forms a mesh to trap red blood cells, which eventually dries to form a scab.

Lymphatic System

  1. All chambers are relaxed and blood flows into the heart
  2. Atria contract, pushing blood into ventricles
  3. After atria relax, ventricles contract, pushing blood out of the heart

Capillaries

Cells need oxygen and nutrients and produce waste products such as CO2 and useful products such as hormones.

Useful substances move out of plasma of capillaries into tissue fluid (fluid in between cells in tissues)

Are constantly supplied with new blood or else diffusion wouldn't occur

Circulation of body fluids and the production of lymphocytes

Lymph node: contain many lymphocytes to filter out lymph

Tissue fluid: made when plasma is squeezed out of capillaries

  1. Substances diffuse between cells and tissue fluid
  2. Lymph vessels collected lymph and return it to the blood
  3. Tissue fluid returns to the capillaries by osmosis

Immune System

Phagocyte

Lymphocyte

lobed nucleus and vesicles containing digestive enzymes

engulf pathogen, vesicles fuse with vacuole and enzymes digest the bacteria

antigen: protein, carbohydrate on surface of pathogen with provokes the immune system

Found in blood and lymph nodes

Large nucleus producing antibodies

Antibodies: Y-shaped proteins that bind to label pathogens

They're either destroyed by being ingested by the pathogens or the antibodies may do it