Respiratory and circulatory system Flashcards
how is the alveolus adapted for gas exchange?
1 cell thin epithelium
moist lining/sufactant
high conc gradient of CO2/O2 due to good blood supply
many and small tf large SA for diffusian
what is ventilation?
breathing in and out
what happens in inhalation?
external incostal muscles contract, expanding ribcage outwards and upwards. diaphragm contracts, pulling downwards to increase volume of the chest. Pressure inside chest is lowered and air is sucked into the lungs.
What happens in exhalation?
The internal muscles contract. The rib cage drops inwards and downwards. Diaphragm relaxes moving upwards, decreasing volume of chest ∴ pressure increases so air forced out of lungs
How is the respiratory system adapted for efficient gas exchange?
- many alveoli ∴ large SA ∴ greater area for diffusion
- RBCs have no nucleus ∴ can carry lots of haemoglobin for O2
- one cell thick epithelium ∴ small diffusion distance
Why can unicellular organisms rely on diffusion for transport but we can’t?
- they have a large SA/V ratio ∴ can rely on diffusion
- we are bigger, w a smaller SA/V ratio ∴ can’t get enough O2 via skin ∴ need a transport system
What are the effects of smoking?
Tar build up in lungs:
-causes lung cancer as has carcinogens
-alveoli are damaged by chemicals ∴ emphysema, so less O2 uptake
-cilia in bronchioles paralysed ∴ waste and debris build up and aren’t removed ∴ lung infectious and bronchitis
Nicotine:
-contracts arteries ∴ reduces blood flow ∴ fat deposited in blood vessels ∴ high blood vessels and risk of stroke/heart attack
CO:
-binds to haemoglobin ∴ reduces O2 carrying capacity of RBCs causing tiredness, dizziness, incr heart rate
What is an experiment to look at the effect of exercise on breathing in humans?
- somebody cycle on machine for 2 mins, whilst breathing rate monitored. Allow them to rest
- repeat for 4, 6, 8, and 10 mins allowing to rest after each one
- repeat w several ppl
What is the difference between breathing and respiration?
- breathing is mechanical action of getting air in and out of lungs
- respiration is chemical action producing energy for cells
How are mitochondria adapted for respiration?
Matrix like system ∴ high SA ∴ more gases diffuse over it, and more resp
What is the respiration equation?
Glucose (C6H12O6) + oxygen (6O2) ⇒ carbon dioxide (6CO2) + water (6H2O) + ATP
What is anaerobic respiration in humans? When does it happen?
Glucose ⇒ lactic acid + ATP
• at end of exercise when not enough O2 but need energy
• happens in muscles
• glucose not fully broken down ∴ not as much energy released as aerobic
Why do we still need O2 after exercise?
• need to break down lactic acid produced
Lactic acid + oxygen ⇒ CO2 + water
• ∴ we have an oxygen debt after exercise as additional O2 still needed ∴ we pant
What is an experiment to demonstrate the production of CO2 in respiration?
Set up four beakers (soda lime, lime water, germinating seeds, limewater) w tubes between them.
Sodalite gets rid of CO2, lime water proves no CO2 at this point, as would turn cloudy, germinating seeds need energy ∴ respire, lime water turns cloudy ∴ proving CO2 made from resp
T demonstrating the production of heat in resp?
Get two beakers. Put germinating seeds in one and boiled (dead) in the other. Place wet cotton wool with a thermo in it at the top.
Germinating seeds will respire, as resp is exo ∴ temp rises. Dead seeds can’t respire ∴ temp stays same
How and why does respiration change during exercise?
- need resp rate inc to get more energy to muscles
- breathing rate and depth of breaths incr to max amount of O2
- heart rate incr to pump O2 around body
- body temp incr as resp exo ∴ heat let out, and not all energy from resp converted to KE
- more CO2 breathed out as by porridge of resp
- epinephrine stimulates adrenergic receptors in heart to inc heart rate
What are the components of blood? (4)
RBCs, WBCs, platelets and plasma
What does plasma do?
Transports stuff, e.g. Urea, hormones, CO2, O2, antibodies, digested food prods, around body. Mostly made of water. Also helps regulate temo and blood pres
What do RBCs do and how are they adapted to it?
Transport O2 from lungs to rest of body and CO2 back to lungs.
No nucleus ∴ more space for haemoglobin ∴ can carry more O2
Small and bioconcave shape ∴ large SA for efficient diffusion of O2 and CO2
Haemoglobin ∴ binds to O2 in lungs ⇒ oxyhaemoglobin, reverse in tissue to release O2
Thin outer membrane ∴ shorter diffusion distance
What do the arteries do? How are they adapted to this?
- carry blood away from heart
- blood at high pres to pump a round body, ∴ thick tunica externa to be strong and thick layers of muscle and elastic fibre to stretch as blood surges through. Smooth tunica interna ∴ less friction
What do the veins do? How are they adapted to this?
- carry blood to heart
- blood at Lowe pres ∴ walls don’t have to be as thick
- have valves to ensure blood keeps flowing in right direction
- walls less elastic ∴ lowers pres
What do the capillaries do? How are they adapted to this?
- small. Link arteries and veins, allow food molecules and O2 into cells and waste to diffuse out of cells
- v thin, permeable walls, only 1 cell thin ∴ reduce diff distance
- small but large cross sectional distance to allow for efficient transfer of oxygenated blood cells
What happens in one cycle of the heart?
- deoxygenated blood from body enters via vena cava into right atrium.
- blood pumped via tricuspid valve into right ventricle, then via pulmonary valve into pulmonary artery where it goes off to lungs and it oxidised
- oxygenated blood comes into left atrium from pulmonary vein and goes into left ventricle via mitral valve
- blood then goes via aortic valve into aorta and around rest of body
Why does the left ventricle have a thicker wall than the right ventricle?
Herat needs more muscle to pump blood around body, as it must be at high pres as going to whole body, not just lungs
What is a double circulatory system?
What mammals have
Pulmonary circuit transports blood to lungs. Systemic circuit transports it around the body
What is the circulatory system?
- from head and army deoxygenated blood goes in vena cava to heart then into pulmonary artery, where it is oxygenated.
- blood then goes into pulmonary vein, through heart then into aorta
- aorta splits into 3 branches: hepatic artery supplies stomach, liver, pancreas and duodenum. Hepatic portal vein takes blood to pancreas. Blood leaves via hepatic vein
- renal arteries supplie blood to kidneys, goes back via renal vein.
What does the placenta do?
- attarches umbilical cord to uterine wall
- provides O2 and nutrients (e.g. Glucose) from mother’s blood supply
- transfers waste products (CO2, urea) from baby via umbilical cord to mother’s bloodstream
- produces hormones to help baby grow and develop
What does the amniotic fluid do?
Protects and cushions the embryo
