human transport

advantages of a single circulatory system :

• less complex

disadvantages of a single circulatory system :

• lower delivery rate because of lower pressure

• organism moves slower

advantages of a double circulatory system :

• higher pressure so that blood can pump further

• faster blood flow

description of a insects circulatory system :

• no blood

• open circulatory system

• haemolymph pumped by heart, diffuses through short channels to the haemocoel, when heart relaxes, blood is sucked back through the ostia

• slow metabolic rate

• high surface area to volume ratio

• transports molecules e.g. hormones, nutrients

what is heamolymph?

fluid equivalent to blood without red blood cells and haemoglobin

What is haemocoel?

the primary body cavity in insects that fills with circulatory fluid

description of a fish’s circulatory system :

• single circulatory system

• countercurrent system with blood

• higher metabolic rate

• large surface area to volume ratio

• transports molecules e.g. hormones, enzymes

description of a human circulatory system :

• molecules transported through the blood

• double circulatory system

• small surface area to volume ratio

what is a double circulatory system?

blood flows through the heart twice per heart beat

why do fish have a single circulatory system?

• don’t have to pump blood as far

• don’t have to fight against gravity

what is a single circulatory system?

the blood is contained within blood vessels

what is a partial double circulation?

• oxygenated blood isn’t completely separate

• ventricles and aorta not separate

• blood still passes through the heart twice per heart beat

why is a partial double circulatory system less effective than a double circulatory system?

• oxygenated and deoxygenated blood is mixed

• lower saturation of oxygen in blood

• lower pressure

why do larger organisms need a circulatory system?

• higher metabolic rate - need a more rapid supply

• small SA : Vol ratio - diffusion doesn’t supply sufficient oxygen

what do elastic fibres do in blood vessels?

stretch and recoil

what does smooth muscle do in blood vessels?

contract and relax with the beat of the heart changing the size of the lumen

what does collagen in blood vessels do?

provide structural support maintaining shape and volume

features of arteries :

• less muscle more elastin - can pulse to move blood

• narrow lumen - creates high pressure

• high collagen to prevent rupture

features of veins :

• valves - prevent back flow of blood

• no vein pulses because blood pressure is low

• wide lumen - to move blood quickly back to heart

• little smooth muscle - does not need to contract

features of a venule :

• no elastin or smooth muscle

features of an arteriole :

• more muscle less elastin - helps pulse surges maintain high blood pressure

features of a capillary :

• one cell thick - more efficient diffusion to deliver oxygen

• thin epithelium tissue

• gaps in capillary wall (endothelium) for larger substances

• large surface area

what are the two types of circulatory systems involved in a double circulatory system?

systemic and pulmonary

what is A?

bundle of his

what is B?

right and left branches of purkyne tissue

what is C?

purkyne fibres

what is D?

atrio- ventricular node

what is E?

sino - atrial mode

what happens during diastole?

• semi lunar valves close

• all heart muscles relax

• blood flows into atria

• blood pressure remains low

what happens during atrial systole?

• muscles in the atria contract

• pressure increases

• semi lunar valves close

• atrioventricular valves open

what happens during ventricular systole?

• ventricle muscles contract

• pressure increases

• atrioventricular valves close

• semi lunar valves open

• blood flows out through aorta and pulmonary artery

what is haemoglobin made of?

• four polypeptide chains each bound to one haem group

• each haem group can combine with one oxygen molecule

what is the term when all haem groups of haemoglobin have bound to a oxygen molecule?

oxyhaemoglobin

what is partial pressure?

the concentration of gas in a mixture of gases

what is partial pressure measured in?

kilopascals (kPa, PO2)

describe and explain the graph :

• at start rapid increase - when one oxygen binds it changes shape of the protein therefore increasing affinity

• higher partial pressure - higher affinity and therefore higher saturation

• plateaus as the haemoglobin becomes saturated

what are three ways carbon dioxide is transported?

• dissolved in plasma (5%)

• combined with amino groups to form carbaminohaemoglobin (10-20%)

• converted to hydrogen carbonate ions in cytoplasm of rbc (75-80%)

how does carbaminohaemoglobin form?

when carbon dioxide binds to haemoglobin

what is the bohr shift?

• affect of high carbon dioxide concentration on haemoglobins affinity for oxygen

• line drawn to right of normal curve

• decrease haemoglobins affinity for oxygen

• more oxygen is released for respiration

• more carbaminohaemoglobin is formed

why does foetal haemoglobin have a higher affinity for oxygen?

• needs to be able to bind with oxygen at a lower partial pressure

• maintain a diffusion gradient from placenta

• line to the left of normal curve

what is myoglobin?

• similar to haemoglobin but with only one haem group

• higher affinity for oxygen at very low partial pressure

• reserve storage molecule found in muscle cells

how are hydrogencarbonate ions produced in ethrythrocytes?

• carbon dioxide diffuses into ethryocytes

• reacts with water

• forming carbonic acid

• the carbonic acid dissociates to form hydrogen carbonate ions and hydrogen ions

what is hydrostatic pressure?

blood pressure - wants to force fluid out of the capillaries

what is oncotic pressure?

pressure caused by plasma protein which reduce the water potential encouraging water to move into capillaries

• plasma protein are too big to leave

what is happening at the arterial end of a capillary?

• hydrostatic pressure larger than oncotic

• net movement of fluid out of capillaries

• tissue fluid bathes the cells and exchanges substances with them

what happens at the venous end of the capillaries?

• oncotic pressure stays the same - same concentration of plasma proteins

• blood moves slower - lower hydrostatic pressure

• net movement is into the capillaries

what is the order of layers of a artery inwards to outwards?

• endothelium

• smooth muscle

• connective tissue

what is the sound of ‘lub dub’ in the heart caused by?

closing of the atrioventricular valves then semi lunar valves

why would animals living in high altitudes dissociation curve be to the right?

their haemoglobin needs a higher affinity for oxygen to gain enough oxygen when partial pressure is low

how does electrical the sino atrial node do?

• send a charged wave of depolarisation flows through atria walls

• causes walls to contract

• blood forced through atria ventricular valves

• slight delay then ventricle walls contracts

• blood flows out of the aorta and semi lunar valves

what does collagen (non-conducting tissue) do within a heart beat?

prevents electrical activity from entering the ventricles

what does the atria ventricular node do?

• picks up wave of depolarisation

• sends to bundle of his

what does purkyne tissue do?

conduct the electrical activity of the heart

why do maggots have a less developed transport system than flies?

• lower metabolic rate

• - larger surface area to volume ratio

• shorter diffusion distance

sequence of a ECG of a healthy heart :

PQRSTU

what is the P wave of a normal ECG?

depolarisation of the atria causing them to contract

what is the QRS complex of a normal ECG?

depolarisation of the ventricles causing them to contract

• largest wave as ventricles have the largest muscle mass

what is the T wave of a normal ECG?

repolarisation of the ventricles causing them to relax

what is the U wave of a normal ECG?

potentially repolarisation of the purkyne fibres

what is tachycardia?

when the heart beats too fast

what is bradycardia?

when heart beats too slow

what is an ectopic heartbeat?

an early heartbeat followed by a pause

what is fibrillation?

an irregular heartbeat which disrupts the rhythm of the heart