Summary Transport in animals

TRANSPORT PG 79 - 106


TRANSPORT IN ANIMALS
CHARACTERISTICS OF CIRCULATORY SYSTEMS:

ð BLOOD: Transport dissolved gases, nutrients, waste products
around body
ð BLOOD VESSELS: Blood flows around body
ð HEART: Pump blood around the body
ð VALVES: Ensure blood flows only in one direction
Know names & purpose

TYPES OF CIRCULATORY SYSTEMS:

- OPEN
- CLOSED

OPEN SYSTEM:

ð Open circulatory system [smaller organisms]: blood pumped at
low pressure from heart into haemocoel [main body cavity]
ð Blood: bathes internal organs à returns to heart
\ open systems: inefficient

CLOSED SYSTEM:

ð Closed circulatory system [larger organisms]: Blood enclosed &
circulates blood vessels.
ð Tissue fluid: found between blood vessels & cells
ð Closed system: effective transport system à allows blood: travel
rapidly under high pressure.

,TRANSPORT PG 79 - 106


THE HUMAN CIRCULATORY SYSTEM:

ð Humans: closed circulatory system
Cardiovascular system à Blood: flows to distant parts of body &
back to heart

HUMAN CIRCULATORY SYSTEM – A DOUBLE SYSTEM:

ð Heart: 2 pumps
- Right: pumps blood to lungs à returns to left side
- Left: blood pumps to rest of body à returns to right side of heart
ð \ Blood flows through 2 distinct circulations: pulmonary &
systematic à DOUBLE CIRCULATORY SYSTEM
Cardiac system part of system part of systemic
- Pulmonary circulatory system: deoxygenated, high pressure
blood flows from right heart to lungs
Oxygenated blood: flows from lungs à left heart.
- Systematic circulatory system: carries oxygenated blood from
left heart to all body cells.
Deoxygenated blood: flows from body tissues to right heart à
major part of circulatory system

ADVANTAGES OF A DOUBLE CIRCULATORY SYSTEM:

- PULMONARY [1st system]: Blood pumped to lungs for gaseous
exchange
- SYSTEMIC [2nd system]: Blood pumped under pressure to all body
parts à supply w/ oxygen nutrients & take up CO2, other wastes

VALUE OF OTHER PRESSURE:

ð Blood under pressure allows:
- Tissue fluid to form [provides medium: substances move between
blood & cells]
- Oxygen [O2] to be carried out quickly [for cellular respiration]

, TRANSPORT PG 79 - 106


THE HEART:

ð HEART: Pump applying pressure to force blood around body.
ð Situated: middle of chest/ thorax in mediastinum [space between
lungs]

EXTERNALLY:

- Surrounded by pericardium [2 inelastic membranes]
Fluid between these membranes à allowing: move easily,
preventing friction
- Coronary arteries: supply heart muscles w/ nutrients, O2
Blockage of these vessels: starve heart muscles of nutrients, O2 à
heart attack/myocardial infarction/coronary thrombosis
- Heart: have à deposits of fat

INTERNALLY:

ð Divided into four chambers
ž 2 upper chambers: ATRIA [atrium] à small, thin walled
Receiving chambers: collect blood from veins, push into
ventricles
ž 2 lower chambers: VENTRICLES à thick walls
Contract, push blood out heart to body parts
- Left ventricle wall: v/ thick à pump blood right around body
- Right ventricle: not as thick à only have to pump to lungs
ð MYOCARDIUM: Layer of heart wall made up of cardiac muscle
[special muscle tissue]
unique: contracts rhythmically w/out getting tired
ð SEPTUM: Divides heart into left and right sides.
ð ENDOCARDIUM: Smooth membrane lining the heart [made of
endothelial tissue]
ð Ventricles: have papillary muscles forming tendinous cords à
extending to atrioventricular valves.