Chapter 3: Functioning Systems

Question 1

Vascular plant

Answer 1

Plant containing vascular tissue = phloem and xylem tissues in plants

Question 2

Vascular tissue

Answer 2

The plant tissue for the transport of water, nutrients, sugar and other substances in the xylem and phloem

Question 3

Root System

Answer 3

The root system is the parts below the ground - it’s responsible for anchoring the plant and water and mineral uptake from the soil.

Question 4

Shoot System

Answer 4

The shoot system is above the ground - it’s responsible for transporting food and the exchange of gases during photosynthesis

Question 5

Characteristics of Xylem

Answer 5

• Made up of lignin
• Thicker than phloem
• Transports water and minerals
• One way movement - Upward only
• Composed of dead cells - tracheids and xylem vessels

Question 6

Characteristics of Phloem

Answer 6

• Made up of cellulose
• Thinner than xylem
• Transports sugars (food)
• Two way movement - both upward and downward
• Composed of living cells - companion cells, sieve tube cells

Question 7

TRANSPIRATION

Answer 7

Transpiration is the loss of water through the stomata. It happens with the help of two processes: transpiration stream and transpiration pull.

Question 8

Transpiration Stream

Answer 8

is the evaporation of water from root to leaf with the help of the sun heating the plant.

Question 9

Transpirational Pull

Answer 9

is the upward movement of water through the xylem vessels with the help of cohesion and adhesion.

Question 10

Cohesion

Answer 10

is the attraction between like particles (that is the water molecules)

Question 11

Adhesion

Answer 11

is the attraction between the unlike particles (that is the water and the xylem vessel).

Question 12

Together what does cohesion and adhesion assist in?

Answer 12

assist with the upward pull of water.

Question 13

Stomata

Answer 13

The leaf of a plant has a waxy cuticle on top which has low permeability and a matte underside which has more permeability.

Question 13

Where is the opening of the stomata located?

Answer 13

Mostly found underneath the leaf.

Question 14

What does the Stomata do?

Answer 14

is an opening for the transpiration of water but also the exchange of gases during photosynthesis.

Question 15

Formula of Photosynthesis

Answer 15

Carbon dioxide (gas) + water → glucose + oxygen (gas)

Question 16

Opening of the stomata

Answer 16

• Stomata pump K+ (potassium) ions into guard cells
• Water moves in via osmosis
• Guard cells swell which enables stomata to open and water to exit via transpiration

Question 17

Closing of the stomata

Answer 17

• To close the stomata, K+ ions leave the guard cells
• Water leaves the guard cells via osmosis
• The stomata close – conserving water

Question 18

Pituitary gland - “called the master gland as it also releases hormones that control other glands”

Answer 18

Hormone produced : Antidiuretic hormone (ADH)
Function of Hormone : Stimulates the reabsorption of water in the loop of Henle

Question 19

Thyroid gland

Answer 19

Hormone produced : Thyroxine
Function of Hormone : Increases basal metabolic rate (rate of energy expenditure) and therefore oxygen consumption

Question 20

Pancreas

Answer 20

Hormone produced : Insulin and Glucagon
Function of Hormone : Insulin increases uptake of glucose thereby lowering blood sugar levels + increases glycogen (stored form of glucose) storage by liver. Glucagon stimulates conversion of glycogen back into glucose

Question 21

Adrenal Gland - located on top of kidneys

Answer 21

Hormone produced : Adrenaline and Cortisol
Function of hormone : Adrenaline constricts the blood vessels and stimulates the release of glucose
(Also increasing the heart rate, increasing blood pressure, expanding the air passages of the lungs)
Cortisol helps the body manage stress.

Question 22

Testes

Answer 22

Hormone produced : Testosterone
Function of Hormone : For maturation of sperm cells / reproduction

Question 23

Ovaries

Answer 23

Hormone produced : Oestrogen
Function of Hormone : For maturation of egg cells / reproduction

Question 24

THE MAMMALIAN DIGESTIVE SYSTEM consists of:

Answer 24

Digestion consists of 4 main steps: ingestion, digestion, absorption and egestion

Question 25

Steps of Digestion

Answer 25

1. Food is ingested and broken down physically with the help of teeth (mechanical digestion). While the food is in the mouth the salivary glands release saliva which has enzymes. The enzyme amylase in the saliva breaks down complex carbohydrates to simpler ones and mucin softens the food. The food that is lumpy is now called a bolus.
2. The bolus is swallowed and moves into the oesophagus through muscular contractions called peristalsis. The oesophagus ends at the oesophageal sphincter which connects to the stomach.
3. The bolus then passes into the stomach through the oesophageal sphincter. In the stomach, food is chemically digested by gastric juice. Gastric juice is produced via the sensory cells of the stomach wall. It is made up of mucus, water, hydrochloric acid and the enzyme pepsin. It is highly acidic and has a pH of 1.5 to 3. The bolus is also mechanically digested with the churning action of the stomach. Once the bolus becomes a soupy mixture it is called chyme.
4. At the end of the stomach is the pyloric sphincter. Chyme passes through the pyloric sphincter and arrives at the duodenum (the first part of the small intestine).
5. The pancreas secretes pancreatic juices which consist of the enzymes amylase, trypsin and lipase as well as bicarbonate. The bicarbonate neutralises the acidity in the duodenum. The duodenum has an alkaline pH at 7-8.5.
6. At the same time the gallbladder releases stored bile into the duodenum to break down fat. Bile mechanically breaks down fat into fatty acid and glycerol through a process called emulsification. (Bile is produced by the liver).
7. The food then moves into the ileum of the small intestine. Most absorption takes place here through tiny finger-like projections called villi. The nutrients move into the villi and then into the bloodstream (to get to our cells) as the villi is surrounded by capillaries.
8. The remaining waste moves into the colon (large intestine). Here water and salts are absorbed back into the bloodstream.
9. What’s left over is solid waste (faeces). The faeces pass into the rectum and once ready exit the body via the anal sphincter at the anus. This is called egestion.

Question 26

THE MAMMALIAN EXCRETORY SYSTEM

Answer 26

The kidneys remove metabolic waste and regulate the concentration of bodily fluids.

This is done by adjusting the amount of water reabsorbed back into the tubules and the amount of salt secreted in the urine.

Question 27

What is the Nephron?

Answer 27

is the functional unit of the kidney. Filtration of the blood takes place here.

Question 28

Filtration of blood process

Answer 28

• The blood enters the kidney via the renal artery and into the cortex/medulla of the kidney where the nephrons are
• The blood then enters the nephron through the afferent arteriole into the glomerulus
• The glomerulus filters the blood. The clean blood exits the glomerulus via the efferent arteriole
• The waste produced via the filtration of the glomerulus is the glomerular filtrate.
• Glomerular filtration is the first step in making urine. It is the process that your kidneys use to filter excess fluid and waste products out of the blood into the urine collecting tubules of the kidney, so they may be eliminated from your body.
• The glomerular filtrate then passes through the proximal convoluted tubule where reabsorption starts (mainly of ions)
• The filtrate then moves into the loop of Henle where reabsorption of water takes place.
• Antidiuretic hormone (ADH) stimulates the reabsorption of water at the loop of Henle along with counter current systems consisting of ions that draw water in (via osmosis) and promote reabsorption.
• It then moves into the distal convoluted tubule where final reabsorption takes place then makes its way into the collecting duct to be released into the kidney to exit via the ureter as urine which gets collected in the bladder. The urine is then excreted via the urethra