Chapter 12: Animal Systems

Question 1

What are 3 general components in a circulatory system?

Answer 1

1. A fluid in which materials are transported (blood)
2. A system of interconnected blood vessels or spaces where the fluid moves
3. A muscular pump (heart) that puches the fluid through the vessels or spaces

Question 2

What is an open circulatory system?

Answer 2

A circulatory system where transport fluid washes freely over the internal organs, they are less efficient than closed circulatory systems

Question 3

What is the fluid in open circulatory systems?

Answer 3

Haemolymph

Question 4

How does haemolymph circulate the body and deliver substances to cells in an open circulatory system?

Answer 4

Via the body cavity, substances enter the cells via diffusion

Question 5

How does blood circulate the body and deliver substances to cells in a closed circulatory system?

Answer 5

Flows through enclosed blood vessels

Question 6

What is a single circulatory system?

Answer 6

Only has one circuitof bloodflow eg. in fish

Question 7

What is a double circulatory system?

Answer 7

System that has two circuits, The pulmonary circuit (transports deoxygenated blood to the lungs and back to the heart), and the systemic circuit which pumps oxygenated blood around the body and back to the heart. eg. mammals

Question 8

What are the 4 principal functions of the mammalian circulatory system?

Answer 8

1. Transportation of water, oxygen and carbon dioxide
2. Distribution of nutrients and removal of wastes
3. Maintenance of body temp
4. Circulation of hormones

Question 9

What is the structure and function of erythrocytes (red blood cells)?

Answer 9

Contain haemoglobin, a molecule that allows the cell to bind oxygen molecules. Dont have a nucleus in their mature stage, allowing the cell to carry more haemoglobin.

Question 10

What is the function of leukocytes (white blood cells)?

Answer 10

Function is to protect the body against invading micro-organisms and toxins. Some types destroy microorganisma by engulfing them and using enzymes to digest them

Question 11

What is the structure and function of platelets?

Answer 11

To initiate blood clotting. When the platelet membrane breaks, it releases a substance that reacts with protiens in plasma to create a mesh of fibers, preventing further blood loss.

Question 12

Explain the process of how blood flows through the heart and other body systems.

Answer 12

Deoxygenated blood enters the right atrium through the vena cava, and goes into the right ventricle (from systemic circulation). When the right ventricle contracts it pushes blood into the pulmonary artery where blood goes to the lungs (pulmanory circulation) to be reoxygenated. The oxygen rich blood goes back into the heart through the left atrium then into the left ventricle, where the blood then flows into the aorta, where it goes to all the body systems and the cycle restarts.

Question 13

What is the lymphatic system?

Answer 13

A series of lymph vessels that allow proteins and water that hasn’t diffused into cells from the blood stream to flow back to the heart and rejoin the bloodstream.

Question 14

What are the 2 forms of digestion? Explain them

Answer 14

• Mechanical digestion:
  When large peices of food are broken down through chewing or muscular movement in the stomach. Aim is to increase surface area of the food so enzymes can act more effectively.
• Chemical digestion:
  When enzymes break down complex substances into their simplest form so they can be absorbed into the bloodstream

Question 14

What are 5 factors that effect the rate of gas exchange

Answer 14

• Large surface area for diffusion
• Highly vascularised (lots of blood vessels)
• Concentration gradient
• Moist environment for gasses to dissolve and diffuse
• Thin and permeable, short diffusion path

Question 15

What are the 4 main roles of the digestive system? Explain them

Answer 15

1. Ingestion: Taking in nutrients
2. Digestion: Breaking down complex molecules into simple ones
3. Absorption: Taking up the digested molecules
4. Egestion: The removal of undigested waste from the body

Question 16

What is an alimentary canal?

Answer 16

The specialised pathway food takes in complex animals. Includes the passage from mouth to anus and the organs the food passes through.

Question 17

What is the alimentary canal in humans?

Answer 17

Mouth, oesophagus, stomach, small intestine, large intestine, rectum, anus

Question 18

What enzyme is secreted from saliva glands and what does it break down?

Answer 18

Amylase, breaks down complex carbohydrates

Question 19

What does the epiglottis do?

Answer 19

Closes off trachea so food goes down the oesophagus.

Question 20

What is the main focus of digestion in the stomach?

Answer 20

Chemical digestion of protiens

Question 21

What is digested in the small intestine?

Answer 21

• Polysaccharides (carbs)
• Polypeptides (proteins)
• Fats

Question 22

Where are most nutrients absorbed in digestion?

Answer 22

Small intestine

Question 23

What are villi?

Answer 23

Projections from the surface of the small intestine that increase surface area and absorbtion of nutrients. Glucose and amino acids are absorbed into the capillary network, while fatty acids are absorbed in the lymphatic system.

Question 24

What are the main functions of the large intestine?

Answer 24

• Compact undigested food material
• Absorb water and salts back into the body
• Pushing wastes into the rectum and out the anus

Question 25

What are 3 specialised features of herbivores arlimentary canals?

Answer 25

• Molars for grinding plant material
• Incisors and canines to bite off vegetation
• Enlarged stomach with 4 chambers (ruminant)

Question 26

What are the 4 stomach chambers in ruminant herbivores and what are their functions?

Answer 26

• Abomasum (whole stomach)
  1. Reticulum: Forms balls of cud to be regurgitated and chewed again
  2. Rumen: When cud is swallowed, mixes with cullulose digesting bacteria and saliva, then fements releasing CO2 and methane.
  3. Duodenum: where products of digestion are absorbed

Question 27

What are 3 specialised features of carnivores arlimentary canals?

Answer 27

• Pointed incisors and canines
• Jagged molars, both to kill prey and rip flesh during their meal

Question 28

What are 3 main differences between the alimentary canals of herbivores and carnivores?

Answer 28

• Herbivores have larger alimentary canals than carnivores
• Different enzymes for breaking food down
• Carnivores can ansorb nutrients faster than herbivores