B5 - The human body

Question 1

What is the job of the lungs during gas exchange? explain process

Answer 1

the lungs transfer oxygen and remove co2 from the blood
lungs contain millions of tiny little air sacks called alveoli where gas exchange takes place
alveoli are surrounded by tiny blood vessels called capillaries, this is where gas exchange takes place.
oxygen from the alveoli diffuses into the capillaries, co2 opposite happens

Question 2

how are alveoli specialised to maximise the rate of diffusion of o2 and co2?

Answer 2

• enormous surface area
• moist lining for dissolving gases
• good blood supply
• thin walls

Question 3

explain the two circuits of the double circulatory system

Answer 3

first circuit: heart pumps deoxygenated blood to the alveoli for oxygen. The oxy blood then returns to the heart
second circuit: heart pumps oxygenated blood all around the other organs of the body; oxy given up at the body cells. Returns!!

Question 4

What are the 4 chambers?

Answer 4

right and left ventricles and artria

Question 5

What are the valves in the heart?

Answer 5

makes sure the blood flows in the right direction
when the ventricles contract, the valves to the atria close and the valves to the blood vessels open, preventing backflow

Question 6

What are the arteries and its adaptations?

Answer 6

the heart pumps the blood out at high pressure, so the artery walls are strong and elastic
they contain thick layers or muscle to make them strong and elastic fibres to allow them to stretch and spring back

Question 7

What are the capillaries and its adaptations?

Answer 7

Tiny
Carry blood really close to every cell in the body to exchange substances with them
They have permeable walls, so substances can diffuse in and out

Question 8

What are the veins and its adaptations?

Answer 8

the blood is at low pressure so the walls aren’t as thick as the arteries
bigger lumen for blood flow
also valves to prevent backflow

Question 9

What is plasma?

Answer 9

pale yellow liquid??

Question 10

what does plasma carry?

Answer 10

red blood cells, white blood cells, and platelets
water
food products
urea
hormones
antibodies

Question 11

red blood cells?

Answer 11

transport oxygen from the lungs to all the cells in the body

Question 12

what are the adaptations of red blood cells?

Answer 12

1. small biconcave disc shape to give a large surface area to vol ratio, which increases the rate at which oxy can diffuse out of the cell
2. packed with haemoglobin
3. don’t have a nucleus for more space for haemoglobin to carry more oxygen
4. small and flexible - they can pass through tiny capillaries close to the blood cells

Question 13

What are sensory receptors?

Answer 13

sensory receptors detect changes in your external/internal environment (stimulus). Different sensory receptors detect different stimuli.

Question 14

What happens when a stimulus is detected by receptors?

Answer 14

when a stimulus is detected by receptors, the information is sent as a nervous impulse, along sensory neurones to the CNS

Question 15

What is the CNS?

Answer 15

It’s a processing centre
Coordinates the response of the nervous impulses
CNS then sends info to an effector (muscle / gland) along a motor neurone.
the effector then responds accordingly