Respiratory and circulatory system

Question 1

how is the alveolus adapted for gas exchange?

Answer 1

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

Question 2

what is ventilation?

Answer 2

breathing in and out

Question 3

what happens in inhalation?

Answer 3

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.

Question 4

What happens in exhalation?

Answer 4

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

Question 5

How is the respiratory system adapted for efficient gas exchange?

Answer 5

• 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

Question 6

Why can unicellular organisms rely on diffusion for transport but we can’t?

Answer 6

• 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

Question 7

What are the effects of smoking?

Answer 7

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

Question 8

What is an experiment to look at the effect of exercise on breathing in humans?

Answer 8

• 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

Question 9

What is the difference between breathing and respiration?

Answer 9

• breathing is mechanical action of getting air in and out of lungs
• respiration is chemical action producing energy for cells

Question 10

How are mitochondria adapted for respiration?

Answer 10

Matrix like system ∴ high SA ∴ more gases diffuse over it, and more resp

Question 11

What is the respiration equation?

Answer 11

Glucose (C6H12O6) + oxygen (6O2) ⇒ carbon dioxide (6CO2) + water (6H2O) + ATP

Question 12

What is anaerobic respiration in humans? When does it happen?

Answer 12

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

Question 13

Why do we still need O2 after exercise?

Answer 13

• 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

Question 14

What is an experiment to demonstrate the production of CO2 in respiration?

Answer 14

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

Question 15

T demonstrating the production of heat in resp?

Answer 15

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

Question 16

How and why does respiration change during exercise?

Answer 16

• 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

Question 17

What are the components of blood? (4)

Answer 17

RBCs, WBCs, platelets and plasma

Question 18

What does plasma do?

Answer 18

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

Question 19

What do RBCs do and how are they adapted to it?

Answer 19

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

Question 20

What do the arteries do? How are they adapted to this?

Answer 20

• 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

Question 21

What do the veins do? How are they adapted to this?

Answer 21

• 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

Question 22

What do the capillaries do? How are they adapted to this?

Answer 22

• 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

Question 23

What happens in one cycle of the heart?

Answer 23

• 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

Question 24

Why does the left ventricle have a thicker wall than the right ventricle?

Answer 24

Herat needs more muscle to pump blood around body, as it must be at high pres as going to whole body, not just lungs

Question 25

What is a double circulatory system?

Answer 25

What mammals have

Pulmonary circuit transports blood to lungs. Systemic circuit transports it around the body

Question 26

What is the circulatory system?

Answer 26

• 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.

Question 27

What does the placenta do?

Answer 27

• 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

Question 28

What does the amniotic fluid do?

Answer 28

Protects and cushions the embryo