Multicellular organisms

Question 1

Functions of stem cells

Answer 1

Self renewal (replicate new stem cells)
Potency (differentiate into specialized cells)

Question 2

Components and function of circulatory system

Answer 2

Heart
Blood vessels
Blood
Function - transport useful substances to cells and remove waste from cells

Question 3

Components of the heart

Answer 3

Left and right atrium/ventricle
septum (wall between left and right side)
superior and inferior vena cava
aorta
pulmonary vein and artery
tricuspid and bicuspid valve
pulmonary and aortic valve

Question 4

Steps of heart beat

Answer 4

• heart muscles relax and blood flows into atria
• atria contract and bicuspid and tricuspid valves open allowing blood into ventricles. Pulmonary and aortic valves close.
• bicuspid and tricuspid valves close to stop backflow and pulmonary and aortic valves open. The ventricles contract pushing blood out out of heart. Meanwhile atria relax and fill with blood.

Question 5

Flow of blood through heart

Answer 5

• Enters body via vena cavas to right atrium
• Enters right ventricle via tricuspid valve then towards pulmonary artery via pulmonary valve
• pulmonary artery carries blood to lungs for oxygenation
• oxygenated blood returns to heart via pulmonary veins into left atrium
• bicuspid valve pushes blood into left ventricle
• blood travels to aorta from left ventricle via aortic valve
• oxygenated blood is released to body via aorta

Question 6

What is a pulse

Answer 6

the expansion and contraction of arteries as blood is pumped through it

Question 7

Role of valves

Answer 7

• prevent backflow and ensure enough blood is pushed around the body

Question 8

Role of red vs white blood cells vs platelets

Answer 8

Red - transport oxygen from lungs to body cells
White - (defence) - phagocytes engulf bacteria
- lymphocytes produce antibodies (disease unit)
- Platelets - small fragments of cells which clott blood by sticking to edges of wound and releasing chemicals to clot and prevent blood loss

Question 9

Role of lymphatic system

Answer 9

collect fluid from tissues to return it to bloodstream eg absorbed from capilleries
also produces lymphocytes

Question 10

Properties of gas exchange surfaces (which occurs via diffusion)

Answer 10

thin membrane
large surface area
moist
extensive blood supply

Question 11

Flow of air when breathing

Answer 11

Nasal cavity (or mouth) , pharynx, larynx, trachea, bronchi, bronchioles, alveoli

Question 12

Role of haemoglobin

Answer 12

Found in read blood cells of vertebrates
binds with 4 oxygen molecules (forming oxyhemoglobin). It transports the oxygen to body tissue with low oxygen concentration. The oxygen is then released making deoxyhemoglobin.
ALLOWS RBCS TO CARRY OXYGEN

Question 13

How does partial pressure work in human gas exchange

Answer 13

Partial pressure is determined by the concentration of a gas in the environment

In human:
high co2 pressure and low o2 pressure in the pulmonary artery - opposite in alveoli
some of the oxygen is diffused into blood and some of the co2 is diffused into the alveoli

body cells have low o2 pressure and high co2 pressure, so the same process applies here

Question 14

Roles of digestive system

Answer 14

Ingestion (consuming food via mouth)
Digestion (breakdown complex molecules)
Absorption (taking up digested molecules)
Egestion (removing waste)

Question 15

Mechanical digestion and examples

Answer 15

Breaks down food into smaller pieces - thus increasing the surface area enzymes can interact with
Eg - chewing food and bile in liver

Question 16

Chemical digestion and enzymes

Answer 16

Breaks down complex molecules into simple chemicals that can be absorbed by body

Amylase - breaks down carbohydrates into simple sugars
Protease - breaks down protein into amino acids
Lipase - breaks down lipids into fatty acids and glycerol

Question 17

How does absorption occur

Answer 17

Occurs in small intestine, where villi (fingerlike projections) increase surface area of small intestine allowing for rapid absorption into rich supply of capilleries (absorb glucose and amino acids) and lacteals (absorb fatty acids and glycerol) surrounding SI.