adaptations for transport - animals Flashcards
define haemocoel
space in an insect’s body cavity that fluid is pumped into
define haemolymph
the fluid in insects that bathes the tissues directly, enabling the exchange of substances
define pulmonary circulation
all of the blood vessels involved in transporting blood from the heart to the lungs
define systematic circulation
all of the blood vessels involved in transporting blood from the heart to the rest of the body / tissues (excluding the lungs)
define chordae tendineae
tendons attached to valves in the heart which prevent the valves from prolapsing
define atrio-ventricular valves
valves between atria and ventricles
define semi-lunar valves
valves between major arteries and ventricles
define sino-atrial node
pacemaker found in the wall of the right atrium which sends a wave of depolarisation across the atria
define atrio-ventricular node
bundle of tissue found between the atria and ventricles which delays the wave of depolarisation
define bundle of His
fibres which transmit the wave of depolarisation through the septum to the apex
define purkinje fibres
fibres which transmit the wave of depolarisation into the ventricular walls to allow contraction
define systole
scientific term for contraction
define diastole
scientific term for relaxation
define electrocardiogram
a test used to check the heart’s rhythm and electrical activity
describe an open circulatory system in terms of insects
- fluid is pumped at relatively low pressure from one main long, dorsal tube-shaped heart running the length of the body
- fluid called haemolymph bathes the tissues directly, enabling the exchange substances
- when the heart relaxes, the haemolymph is sucked slowly back to the heart
- there is no respiratory pigment in the insect haemolymph as oxygen diffuses directly to respiring cells through the tracheal system.
describe a closed circulatory system in terms of mammals and fish
- blood circulates in a fully enclosed system of tubes (blood vessels)
- the heart is a muscular pump, pushing blood at high pressure and with a rapid flow rate
- organs are not in direct contact with the blood but are bathed in tissue fluid
- blood contains a respiratory pigment which carries oxygen
describe a closed circulatory system in terms of earthworms
- has dorsal and ventral vessels running the length of the body
- these are connected by five pairs of pseudohearts
- blood contains a respiratory pigment which carries oxygen
describe open circulatory system in terms of :
- blood pressure
- direct contact with organs
- blood is contained in…
- respiratory pigment
- transport of oxygen
BLOOD PRESSURE : low pressure as it is not contained within vessels
CONTACT WITH ORGANS : as the haemolymph leaves the circulatory system it bathes the organs directly
BLOOD IS CONTAINED IN : blood is pumped from a long dorsal tubular heart into spaces within the body cavity
RESPIRATORY PIGMENT : oxygen reaches the gas exchange surface via a tracheal system, so no respiratory pigment is needed to carry oxygen around body
TRANSPORT OF OXYGEN : oxygen is transported directly to tissues
describe the closed circulatory system in terms of :
- blood pressure
- direct contact with organs
- blood is contained in …..
- respiratory pigment
- transport of oxygen
BLOOD PRESSURE : blood is under high pressure as it is contained within vessels
DIRECT CONTACT WITH ORGANS : as blood is contained within blood vessels blood never has direct contact with organs
BLOOD IS CONTAINED IN : blood is always within vessels, which include arteries, veins and capillaries
RESPIRATORY PIGMENT : oxygen diffuses into the blood and is carried around the body in blood bound to haemoglobin
TRANSPORT OF OXYGEN : oxygen is transported from the lungs to the heart and then towards capillaries in body tissues
what are the two types of closed circulatory system? describe them.
SINGLE CIRCULATION
e.g fish
blood passes through the heart once in one complete circulation
DOUBLE CIRCULATION
e.g mammals
blood passes through the heart twice in one complete circulation
what are the two circuits in double circulation?
describe them.
PULMONARY CIRCULATION
all of the blood vessels involved in transporting all the blood from the heart to the lungs
SYSTEMATIC CIRCULATION
all of the blood vessels involved in transporting all the blood from the heart to the rest of the body/tissues
what are the advantages of double circulation?
explain these
- maintains a high blood pressure in the systematic (blood) circulation
- increased rate of flow to the tissue = increased rate of oxygen supply to tissues for aerobic respiration - allows for a lower pressure in the pulmonary (lung) circulation
- prevents build up of tissue fluid in the lungs if pressure was too high - rapid circulation in the systemic circuit
- left side of heart has thicker muscle to generate a high pressure and faster circulation
- right side of heart has thinner muscle because blood travels a shorter distance
The oxygenated and deoxygenated blood is kept seperate. Why is this important?
Maintains a steep concentration gradient for oxygen at the tissues, and carbon dioxide in the lungs for efficient gas exchange
what are the 3 major types of blood vessels that make up the circulatory system called? Describe them.
ARTERIES - transport blood Away from the heart
VEINS - transport blood to the heart
CAPILLARIES - smallest vessels that allow exchange of substances with body vessels
how do the valves work?
- blood tries to flow back
- blood fills the pocket above the valve
- this forces the valve shut
why do veins above the heart have no valves?
gravity will draw blood down towards the heart
The endothelium is the innermost layer of the vessel and is one cell thick. It proves a smooth lining. Capillaries contain only this layer.
Why is this an important feature?
SMOOTH LINING : reduces friction to reduce resistance to flow of blood
ONE CELL THICK: provides a short diffusion distance and easily bathing capillaries in tissue fluid
What is the function of smooth muscle in arteries?
- withstands high blood pressure from the pumping action of the heart
- it can also contract or relax to direct blood flow around the body to cope with high pressure from the heart (vasodilation and vasoconstriction)