Adaptations For Transport In Animals Flashcards
Features of a transport system
- suitable medium to carry materials
- a pump for moving blood
- valves to maintain flow in one direction
What do some transport systems have in addition?
- a respiratory pigment, increasing the volume of oxygen that can be transported
- system of vessels with branching network to distribute to all parts of the body
What is an open circulatory system?
Blood bathes the tissues directly while held in a cavity called the harmoceol
Describe an insects open blood system
Long tubed shape heart stretches the length of the body. Pumps blood at a low pressure into haemocoel, materials are exchanged between blood and body cells
What is a closed circulatory system?
The blood moves in blood vessels
What is a single circulation system?
The blood moves through the heart once in its passage around the body
What is a double circulation system?
Blood passes through the heart twice
What is pulmonary circulation?
Serves the lungs
What is systemic circulation?
Serves the body tissues
What is the advantage of double circulation?
Blood can be pumped around the body at a higher pressure
What is the inner layer of blood vessels?
Endothelium
One cell thick
Surrounded by tunica media
Smooth lining- reduce friction, minimum resistance to blood flow
What is the middle layer of blood vessels?
Tunica media
Contain elastic fibres and smooth muscle
Thicker in arteries than veins
Arteries- elastic fibres allow stretching to accommodate changes in blood flow
Stretched elastic fibres recoil to push blood through the artery- maintains blood pressure
What is the outer layer of blood vessels?
Tunica externa
Contains collagen fibres- resist over stretching
Describe arteries
Carry blood away from the heart
Thick muscular walls withstand bloods high pressure
Branch into arterioles and then capillaries
Describe capillaries
Network that penetrate all tissues and organs
Blood from the capillaries collects into venues which take blood into veins which return it to the heart
Describe veins
Larger diameter lumen
Thinner walls
Blood pressure and flow rate are lower
Semi lunar valves along their length
Definition of myogenic contraction
The heartbeat is initiated within the muscle cells themselves and not dependent on nervous or hormonal stimulation
What is atrial systole
Atrium walls contract and blood pressure in the atria increases
Pushes blood through the tricuspid and bicuspid valves down into the ventricles, which are relaxed
What is ventricular systole
Ventricle walls contract and increase blood pressure in ventricles
Forces blood up through semi lunar valves into pulmonary artery and aorta
Pulmonary artery = deoxygenated blood to lungs
Aorta = oxygenated blood to the rest of the body
Describe diastole
Ventricles relax
Volume of ventricles increases so pressure decreases
Semi lunar valves shut
Atria relax- blood from vena cava and pulmonary veins enter atria
What is the sino atrial node (SAN)?
An area of the heart muscle in the right atrium that initiates a wave of electrical excitation across the atria
What is the atrio ventricular node (AVN)?
The only conducting area of tissue in the wall of the heart between the atria and ventricles, through which electrical excitation passes from the atria to conducting tissue in the walls of the ventricles
Features of red blood cells
Biconcave shape- larger SA, more oxygen diffuses across the membrane+ thinner centre reduces diffusion distance
No nucleus- more room for haemoglobin
Describe plasma
Contains food molecules, waste products, hormones, plasma proteins
Distributes heat
