139858
Description
Mind Map by mawbyharriet, updated more than 1 year ago
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Created by mawbyharriet
almost 11 years ago
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The
Digestive
System
- Role of the Digestion System
- Role:
- To break down the food we eat into smaller molecules that are small enough to
enter the cells of the body. It also absorbs water, vitamins and minerals and
eliminates water.
- To break down the food we eat into smaller molecules that are small enough to
enter the cells of the body. It also absorbs water, vitamins and minerals and
eliminates water.
- Functions:
- Physical and chemical breakdown of foods;
absorbs nutrients; eliminates solid waste.
- Physical and chemical breakdown of foods;
absorbs nutrients; eliminates solid waste.
- Role:
- Define mechanical and Chemical Digestion
- Mechanical - Occurs as a result of chewing which forms bolus to swallow
- Chemical - 2 enzymes released in mouth: i) Salivary amylase -
starch. ii) Lingual lipase - activated in stomach
- Mechanical - Occurs as a result of chewing which forms bolus to swallow
- Role of accessory organs that contribute to digestion
- Salivary Glands
- Liver
- Gall Bladder
- Pancreas
- Salivary Glands
- Digestive System and Homeostasis
- Digestive system consists of:
- Mouth
- Oral cavity formed by cheeks, hard and soft palates and
the tongue. Also includes teeth and salivary glands
- Oral cavity formed by cheeks, hard and soft palates and
the tongue. Also includes teeth and salivary glands
- Salivary gland
- Parotoid
- Sublingual
- Submandibular
- Parotoid
- pharynx
- Oro - and laryngophrynx - function in swollowing
- Oro - and laryngophrynx - function in swollowing
- Oesophagus
- 25cm long muscular tube - secretes mucus
- 25cm long muscular tube - secretes mucus
- Liver
- Stomach
- J shaped organ - connects oesophagus to duodenum -
reservoir for food - secretes gastric juices - secretes gastrin.
- J shaped organ - connects oesophagus to duodenum -
reservoir for food - secretes gastric juices - secretes gastrin.
- Gall bladder
- Large Intestine
- Ileum- Anus. Estimated 1.5m long
- 4 Regions: Caecum, colon, rectum, anal canal
- Epitheluim contains: - absorptive cells - absorbs water -
goblet cells - secretes mucus
- Functions: > Churning, peristalsis and mass movement help to mix food
and move it along the GI tract. > Bacteria in colon carries out final stage of
digestion. > Formation of faeces and defecation. >Absorption of water.
>Absorption of electrolytes and some vitamins.
- Defecation Reflex: >Mass movement push faeces into rectum. > Rectal wall
distends - stimulation of stretch receptors. > Initation of defecation reflex. >
Defecation reflex - opening of sphincter. > External sphincter under voluntary
control.
- Ileum- Anus. Estimated 1.5m long
- Pancreas
- Small Intestine
- Continuous with stomach and leads into large
intestine - 3 m long. 3 Main sections: - Duodenum -
Jejnum - Ileum
- Circular folds, villi and microvilli all increase surface area. (move when pregnant)
- Circular folds, villi and microvilli all increase surface area. (move when pregnant)
- Functions: 1) Segmentations and peristalsis 2) Complete digestion of
most nutrients 3) Absorbs nutrients and water
- Absorption: - Food now in form that can be absorbed into
blood or lymphatic vessels. - Occurs via diffusion, facilitated
diffusion, osmosis and active transport. - 90% of absorption
takes place here
- Continuous with stomach and leads into large
intestine - 3 m long. 3 Main sections: - Duodenum -
Jejnum - Ileum
- anus
- Mouth
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