Human Health And Physiology

Front 1

Explain why Digestion of Large Food Molecules is Essential

Back 1

1. The food we eat is made up of many compounds made by other organisms which are not all suitable for human tissues and therefore these have to be broken down and reassembled so that our bodies can use them.
2. The food molecules have to be small enough to be absorbed by the villi in the intestine through diffusion, facilitated diffusion or active transport and so large food molecules need to be broken down into smaller ones for absorption to occur.

Front 2

Explain the Need for Enzymes in Digestion

Back 2

1. Enzymes break down large food molecules into smaller ones.
2. Speed up the process of digestion
3. Work at body temperature.

Front 3

State the Source, Substrate, Products and Optimum pH Conditions for One Amylase

Back 3

Enzyme: Salivary Amalyse
Source: Salivary Glands
Substrate: Starch
Products: Maltose
Optimum pH: pH 7

Front 4

State the Source, Substrate, Products and Optimum pH Conditions for One Protease

Back 4

Enzyme: Pepsin
Source: Chief Cells in stomach lining
Substrate: Proteins
Products: Small Polypeptides
Optimum pH: pH 1.5 - 2

Front 5

State the Source, Substrate, Products and Optimum pH Conditions for One Lipase

Back 5

Enzyme: Pancreatic Lipase
Source: Pancreas
Substrate: Triglycerites such as fats and oils
Products: Fatty Acids and Glycerol
Optimum pH: pH 7

Front 6

Outline the Function of the Stomach

Back 6

1. Secretes HCL which kills bacteria.
2. HCL provides optimum pH for pepsin.
3. Secretes pepsin for protein digestion.

Front 7

Outline the Function of the Small Intestine

Back 7

1. Intestinal wall secretes enzymes
2. Receives enzymes from the pancreas.
3. Has villi for absorption of food particles

Front 8

Outline the Function of the Large Intestine

Back 8

1. Moves material that has not been digested along.
2. Absorbes water.
3. Produces faeces.

Front 9

Distinguish Between Absorption and Assimilation.

Back 9

Absorption occurs when the food enters the body as the food molecules pass through a layer of cells and into the bodies tissues. This occurs in the small intestine which has many villi that are specialised for absorption. Assimilation occurs when the food molecules becomes part of the bodies tissue. Therefore, absorption is followed by assimilation.

Front 10

Explain How the Structure of the Villus is Related to its Role in Absorption and Transport of the Products of Digestion.

Back 10

1. Many villi increase the surface area for absorption.
2. Epithelium is only one cell layer thick and so food is quickly absorbed.
3. Microvilli on the villi increase the surface area for absorption further.
4. Protein channels and pumps are present in the microvilli for rapid absorption.
5. The mitochondria in the epithelium provide ATP needed for active transport.
6. Blood capillaries are very close to the epithelium so diffusion distance is small.
7. The lacteal takes away fats after absorption.

Front 11

State That the Coronary Arteries Supply Heart Muscle with Oxygen and Nutrients

Back 11

1. The heart has its own blood vessels.
2. Blood passing through the chambers of the heart does not provide nutrient or oxygen to the heart muscle cells.
3. Coronary arteries are branches of the aorta which provide the heart muscle with a supply of oxygen and nutrient.
4. The coronary arteries branch and spread through the heart muscle supplying the individual muscles cells.

Front 12

Explain the Action of the Heart in Terms of Collecting Blood, Pumping Blood, and Opening and Closing of Valves.

Back 12

1. Atria collect blood from veins.
2. Atria contract, atrioventricular valves open.
3. Blood is pumped into ventricles.
4. Ventricle contracts, atrioventricular valves close and semilunar valves open.
5. Blood is pumped into arteries, semilunar valves close.
6. Cycle repeats.

Front 13

Outline the Control of the Heartbeat in Terms of Myogenic Muscle Contraction, the Role of the Pacemaker, Nerves, the Medulla of the Brain and Epinephrine (Adrenaline).

Back 13

1. Heart muscle can contract by itself (myogenic muscle contraction).
2. Pacemaker initiates contractions.
3. One nerve carries messages from the brain to the pacemaker to speed up the beating of the heart.
4. One nerve carries messages from the brain to the pacemaker to slow down the beating of the heart.
5. Adrenaline signals the pacemaker to increase the beating of the heart.

Front 14

Explain the Relationship Between the Structure and Function of Arteries.

Back 14

1. Thick outer layer of longitudinal collagen and elastic fibres prevents leaks and bulges.
2. Thick wall withstands high pressure.
3. Thick layers of circular elastic fibres and muscle fibres to pump blood.
4. Narrow lumen to maintain high pressure.

Front 15

Explain the Relationship Between the Structure and Function of Veins.

Back 15

1. Thin layer with few circular elastic fibres and muscle fibres as blood does not flow in pulses.
2. Thin walls so that nearby muscles can help push blood towards the heart.
3. Thin outer layer of longitudinal collagen and elastic fibers as pressure is low.
4. Wide lumen to accomodate the slow flowing blood.

Front 16

Explain the Relationship Between the Structure and Function of Capillaries.

Back 16

1. Wall is one cell layer thick so distance for diffusion is small.
2. Pores allow plasma to leak out and form tissue fluid. Phagocytes can also pass through pores.
3. Very narrow lumen so that many can fit in a small space.

Front 17

State That Blood is Composed of Plasma, Erythrocytes, Leucocytes (Phagocytes and Lymphocytes) and Platelets.

Back 17

1. Plasma is largely water and makes up about 55% of the total blood volume.
This is the main transporting part of blood and takes advantage of the solvent properties of water.
2. Erythrocytes are the red blood cells.
3. Leucocytes are the white blood cells.

Front 18

State That the Following are Transported by the Blood: Nutrients, Oxygen, Carbon Dioxide, Hormones, Antibodies, Urea and Heat.

Back 18

The items listed above take advantage of the properties of water (as a solvent):
1. Nutrients
2. Carbon dioxide
3. Hormones
4. Antibodies
5. Urea

Or its thermal properties:
1. heat

Front 19

Distinguish Between Ventilation, Gas Exchange and Cell Respiration.

Back 19

Ventilation is the process of bringing fresh air into the alveoli and removing the stale air. It maintains the concentration gradient of carbon dioxide and oxygen between the alveoli and the blood in the capillaries

Gas exchange is the process of swapping one gas for another. It occurs in the alveoli of the lungs. Oxygen diffuses into the capillaries from the air in the alveoli and carbon dioxide diffuses out of the capillaries and into the air in the alveoli.

Cell respiration releases energy in the form of ATP so that this energy can be used inside the cell. Cell respiration occurs in the mitochondria and cytoplasm of cells. Oxygen is used in this process and carbon dioxide is produced

Front 20

Explain the Need for a Ventilation System.

Back 20

1. To maintain the concentration gradients of oxygen ( needen to make ATP cell via respiration) and carbon dioxide (product of cell respiration) in the alveoli.
2. Oxygen needs to diffuse from the alveoli into the blood. Carbon dioxide needs to diffuse from the blood into the alveoli.
3. To do so there must be a high oxygen concentration and a low carbon dioxide concentration in the alveoli.
4. A ventilation system makes this possible by getting rid of the carbon dioxide in the alveoli and bringing in more oxygen.

Front 21

Describe the Features of Alveoli That Adapt Them to Gas Exchange.

Back 21

1. Great numbers increase the surface area for gas exchange.
2. Wall made up of single layer of cells and so are the walls of the capillaries so diffusion distance is small allowing rapid gas exchange.
3. Covered by a dense network of capillaries which have low oxygen and high carbon dioxide concentrations. This allows oxygen to diffuse into the blood and carbon dioxide to diffuse out of the blood.
4. Some cells in the walls secret fluid allowing gases to dissolve. Fluid also prevents the sides of alveoli from sticking together.