form 4 biology chap6 pt6

12

Upload: cikgushaik

Post on 08-Dec-2014

1.380 views

Category:

Education


3 download

DESCRIPTION

 

TRANSCRIPT

Page 1: form 4 Biology chap6 pt6
Page 2: form 4 Biology chap6 pt6

LEARNING OUTCOME 1 Identify the part of the digestive system

where the formation of faeces takes place.

Page 3: form 4 Biology chap6 pt6

LEARNING OUTCOME 2 Describe the formation of faeces.

• Undigested materials fibre (cellulose) + excretory product (bile pigments, dead cells) + bacteria + water enter colon (peristalsis)

• 90% of water + minerals are absorbed into the bloodstream faecal material becomes more solid = faeces.

Page 4: form 4 Biology chap6 pt6

LEARNING OUTCOME 3 Explain the role of microorganisms in the

colon & the effect of antibiotics on them.

•Synthesis of vitamin B12 & vitamin K

•Conversion of cellulose to simple sugar

•B12 : formation of rbc•K : synthesis of blood clotting factors

Page 5: form 4 Biology chap6 pt6

Overuse of antibiotics?

Reduce the good microbial population eg. E.Coli

Page 6: form 4 Biology chap6 pt6

LEARNING OUTCOME 4 Explain defaecation & the importance of high fibre diets.

•Defaecation : the elimination of faeces from the body through the anus.

•Faeces is stored temporarily in rectum full sphincter muscles relax rectal wall contracts the faeces ejected via the anus.

Page 7: form 4 Biology chap6 pt6

THE IMPORTANCE OF HIGH FIBRE DIETS.

The action of peristalsis is stimulated by fibres

A high fibre diet is very important for : Give bulk to the intestinal contents Helps to absorb water Prevent constipation

Page 8: form 4 Biology chap6 pt6

LEARNING OUTCOME 5 What is the problem related to

defaecation?

•Constipation Haemorrhoids (piles) Colon cancer

Page 9: form 4 Biology chap6 pt6

CONSTIPATION

The difficulty or infrequent evacuation of the bowels (elimination of faeces).

Faeces becomes dry & hard difficult to eliminate.

To prevent eat foods high in fibres, drinking more fluid

Page 10: form 4 Biology chap6 pt6

HAEMORROIDS (PILES) Swollen veins in the

rectum or anus.

Constipation EXCESSIVE pressure exerted on the veins.

Itchiness, pain & rectal bleeding when the veins rupture.

Page 11: form 4 Biology chap6 pt6

COLON CANCER Develops gradually.

A cell divides actively form a polyp malignant (month years later).

Symptoms : change in frequency of bowel movement, blood in faeces, abnominal pain, discomfort, weight loss.

Closely link to diet @ is hereditary.

Consume high-fibre & low fat diet.

Page 12: form 4 Biology chap6 pt6