Transport in humans
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- Why do multicellular organisms need special transport systems
- Unicellular organisms
- Transport substances into and out of cells by diffusion/osmosis/transport.
- Relatively slow
- Multicellular organisms
- Transport substances into and out of cells by special transport systems
- Plants: Xylem and phloem
- Animals: Blood and lymphatic systems
- Relatively faster + more effective to support multicellular organisms
- Circulation system
- System of tubes with pumps and valves to ensure the one way flow of blood
- Circulation of vertebrates
- Double circulation
- Heart
- Muscular pump to keep blood circulating throughout the body
- Fills up with blood when relaxes
- Squeezes out blood at high pressure when contracts
- Circulation of vertebrates
- Blood vessels
- Directs blood flow around the body
- Arteries
- Blood vessels that carry blood away from the heart
- Large artery that leaves from the left side of the heart is known as aorta
- Branches into smaller arteries
- Circulation of vertebrates
- Blood vessels
- Arterioles
- Tiny blood vessels that branches out from arteries
- Divide + branches out into very tiny blood vessels known as blood capillaries
- Circulation of vertebrates
- Blood vessels
- Blood capillaries
- Microscopic
- Found between cells + wall of single layer of flattened epithelial which are partially permeable
- Branched repeatedly to provide a large surface area
- Blood pressure lowered
- Blood flow at a slower speed to more time for exchange of materials
- Circulatory system of vertebrates
- Blood vessels
- Venules
- Capillaries join to form small veins called venules
- Veins
- Venules join to form bigger veins to transport blood towards the heart
- Double circulation
- Blood passes through heart twice in one complete circuit
- Consists of pulmonary + systematic circulation
- Pulmonary circulation
- To + from lungs
- Circulation that links lungs to the heart
- Pulmonary arteries transports deoxygenated blood from the heart to the lungs at a lower pressure
- Pulmonary veins transports oxygenated blood from the lungs to the heart
- Function: Transports deoxygenated blood from the heart to the lungs for gas exchange and transports oxygenated blood from the lungs to the left side of the heart
- Systematic circulation
- To + from various body parts except the lungs
- Circulation of blood around the body except the lungs
- Aorta + arteries carry oxygenated blood from the left side of the heart to the rests of the body except lungs at a higher pressure
- Veins + vena cavae transports deoxygenated blood from the rests of the body except the lungs back to the right side of the heart
- Function: Transports oxygenated blood to rests of the body except lungs + transports deoxygenated blood back to the right side of the heart
- Advantages of double circulation
- Blood enters lungs at a lower pressure
- Due to thinner muscle walls at right ventricle
- Blood flows through lungs at a slower speed, so sufficient time for blood to be well oxygenated before returning back to heart
- Advantages of double circulation
- Left ventricles pump oxygenated blood to rests of body at higher pressure
- Oxygenated blood reaches tissues more quickly
- Helps maintain high metabolic rate of mammals
- Advantages of double circulation
- Separates deoxygenated and oxygenated blood
- Single circulation
- Blood only passes through heart once in one complete circuit
- Single circulation
- artery
- ventricle
- atrium
- veins
- gill capillaries
- systemic capillaries
- Single circulation
- Arteries that leave gills transports oxygenated blood to rests of body
- Arteries transport deoxygenated blood from heart to gills for gas exchange
- Veins carry deoxygenated blood from rests of body to heart
- Heart
- conical in shape
- size of a clenched fists
- made up of cardiac muscles
- located in thoracic cavity between lungs
- found between chests bone and vertebral column
- surrounded by pericardium
- Inner membrane in contact with tissues making up heart
- fluid in pericardial membrane reduces friction when heart beats
- Chambers of heart
- Four chambered
- Two upper chambers
- Has thinner muscular walls as they only force blood into ventricles
- Does not need high pressure
- Chambers of heart
- Two lower chambers
- Has thicker walls as they pump blood to rests of body
- Higher pressure
- Right ventricle has thinner walls compared to left ventricle
- Only pumps blood to lungs from heart
- Left ventricle has thicker walls compared to right ventricle
- Pumps blood to rests of body
- Requires higher pressure
- Chambers of heart
- Medium septum
- Located between right and left sides of heart
- Separates oxygenated and deoxygenated blood, and prevents them from mixing
- Chambers of heart
- Superior vena cava
- Aorta
- Aortic valve
- Pulmonary arteries
- Pulmonary veins
- Left atrium
- Bicuspid valve
- Left ventricle
- Septum
- Descending aorta
- Right ventricle
- Inferior vena cava
- Tricuspid valve
- Right atrium
- Pulmonic valve
- Blank one on the left: Pulmonary veins
- Tricuspid and Bicuspid valve
- Known as antrioventricular valves
- Point downwards to allow blood to flow easier from atria to ventricles
- Chordae Tendineae attached to valve flaps to ventricular walls
- Open when pressure in atria higher than ventricles
- Close when pressure in ventricles higher than atria
- Prevents backflow of blood to atria
- Tricuspid valve found between right atrium and ventricle
- Bicuspid valve found between left atrium and ventricle
- Pulmonic and aortic valves
- Known as semi-lunar valves
- Ensure that blood flows in the right direction
- Prevents backflow of blood into the ventricles
- Coronary arteries
- Two small coronary arteries emerge from the aorta
- Coronary arteries transports oxygen and nutrients to heart
- Coronary veins removes wastes and carbon dioxide from heart
- Return blood to coronary sinus which opens directly into right atrium
- Arteriosclerosis
- Stiffening of arteries/ loss of elasticity
- Fatty substances are deposited on the inner surface of coronary arteries
- Narrows lumen of arteries + increases pressure
- Inner surface of the arteries more rough
- Increases risk of blood clots called thrombin, being trapped
- Causes blood flow to decrease, causing insufficient supply of oxygen and nutrients to heart muscles
- May lead to heart attack and tissue death
- Coronary heart diseases
- Arteriosclerosis
- Factors
- Genes
- Obesity
- Diet of high cholesterol + saturated animal fats
- Diabetes
- Emotional stress
- Smoking
- Coronary heart diseases
- Diseases
- Hypertension
- Stroke/heart attack
- Angina
- Prevention
- Proper diet
- Proper stress management
- Avoid smoking
- Regular physical exercise
- Cardiac cycle
- Sequence of events in one complete heartbeat
- One cycle roughly 0.8 seconds
- Short pause between two heartbeats
- Rate of heartbeat depends on age and size on individual
- Atria and ventricles work alternatively
- Diastole = Relaxation
- Systole = Contraction
- The cardiac cycle - (Systole + diastole)
- Atrial and ventricular diastole
- All chambers relax, filling up with blood, AV valves open
- Atrial systole
- Atria forces blood into ventricles
- Ventricular systole
- Ventricles contract, increasing blood pressure
- Causes bicuspid and tricuspid valve to close
- Prevents backflow of blood into atria
- Forces semi-lunar valves to open
- Blood flows from right ventricle to pulmonary arch
- Blood flows from left ventricle to aortic arch
- The cardiac cycle (Systole + diastole)3. Atrial diastole
- Right atrium receives blood from vena cava
- Left atrium receives blood from pulmonary veins
4. Atrial and ventricular diastole- Pressure in ventricles drop, causing semi-lunar valve to close
- Prevents backflow of blood into ventricles
- AV valves open again
- Whole cycle repeats and refilling of blood happens again
- Coronary arteries
- Left main coronary artery
- Right coronary artery