Unit 7 - Human Nutrition Flashcards
Nutrients
Carbs, fats, proteins, vitamin C, vitamin D, calcium, iron, fibre, water
Function of carbs
To provide energy
Function of fats
To provide energy
Function of proteins
For growth and repair
Function of vitamin C
Helps wound healing, good for healthy blood vessels, skin, cartilage & bones
Function of vitamin D
Helps regulate calcium & phosphate in the body, keeps teeth, bones and muscles healthy
Function of iron
Production of hemoglobin for red blood cells and transportation of oxygen
Function of fibre
Helps digestion, moves food & faces along the gut, helps lower risk of Coronary heart disease, type 2 diabetes and bowel cancer
Function of water
About 60% of body mass is water, is needed in almost every process
Vitamin D deficiency
Rickets - Bone pain, weakness in muscles, bone loss with increased risk of fractures & skeletal deformities
Vitamin C deficiency
Scurvy - Severe leg pain or join pain, tiredness, weakness, blue or red spots on the skin that bruise easily, swollen and bleeding gums
Digestive System processes
1.Ingestion
2.Digestion
3.Absorption
4.Assimilation
5.Egestion
Ingestion
The taking in of substances in the body through the mouth
Digestion
Breaking food down into nutrients
Absorption
The movement of small food molecules and ions through the wall of the intestine into the blood
Assimilation
The movement of digested food molecules into the cells of the body where they are needed
Egestion
The passing out of food that has not been digested or absorbed
Process of ingestion
- Food taken in the mouth
- Food forms into a bolus which is swallowed
- Waves of muscle contraction in the walls of the esophagus push bolus into the stomach
Alimentary canal
The ‘gut’
Journey of food
Mouth –> Esophagus –> Stomach –> Small intestine –> Large intestine –> Anus
Parts of the small intestine
Duodenum & Ileum
Parts of the large intestine
Colon & Rectum
Salivary gland
- Produces saliva that is secreted into the mouth
- Saliva mixes with ingested food to make it soft & easy to swallow
- Saliva has amylase, breaks starch into maltose
Liver & Gall bladder
- Liver produces bile
- Bile digests fat
- Bile is stored in the gall bladder & released through the bile duct into the duodenum
Pancreas
- Secretes pancreatic juice
- helps with digestion of proteins, fats and carbohydrates
- Lipase, protease and amylase
- Is alkaline to neutralize gastric juice and because of many hydrocarbonate ions
Physical Digestion
The mechanical digestion or breakdown of food into smaller pieces, done by the teeth & muscular wall of the stomach
Bile
- Bile emulsifies fats into small droplets
- Surface area of fat increases and lets lipase digest fats into fatty acids & glycerol
Four types of teeth
Incisors, canines, pre-molars, molars
Incisors
Sharp, blade-like, for cutting food
Canines
Strong, pointed, for tearing food
Pre-molars
Combine features of canines and molars, for tearing & grinding food
Molars
Broad, fat surface, for crushing and grinding food
Structure of teeth
Enamel, Dentine, Pulp, Nerves, Cement, Gums
Enamel
Outer white layer of teeth, hardest part of the tooth and body, made of calcium phosphate mineral
Dentine
Hard bon-like substance, softer than enamel, majority of tooth, surrounds and connects to pulp
Pulp
Forms center of the tooth, contains blood vessels and nerves
Nerves
Attached to teeth through holes in the bottom of each tooth, lets one know how hard they are biting and if food is hot or cold
Cement
Attached teeth to the jawbone
Gums
Forms a layer around the teeth helping to keep teeth in place
Amylase
- Secreted in salivary glands & pancreas
- Acts in mouth & small intestine
- Breaks starch down into maltose
Lipase
- Secreted in pancreas
- Acts in small intestine
- Breaks fat down into fatty acids and glycerol
Pepsin
- Secreted in the stomach
- Acts in the stomach
- Breaks protein down into amino acids
- Optimum pH - 2
Trypsin
- Secreted in the pancreas
- Acts in the small intestine
- Breaks protein down into amino acids
- Optimum pH - 9
Maltase
- Secreted in the small intestine
- Acts in the small intestine
- Breaks maltose down into glucose
Gastric Juice
- Mixture secreted in the stomach
- Contains hydrochloric acid
- Provides acid pH for enzymes to work
- Kills bacteria in food and denatures harmful enzymes in microorganisms
Chemical digestion
The breakdown of large insoluble molecules into small soluble molecules
Absorption location
- Digested food is absorbed in the small intestine
- Water is absorbed in the small intestine & colon
Adaptations of the small intestine
- Walls of the small intestine are covered in villi
Function of villi
- Absorb amino acids, simple sugar and water
- Increased surface area rapidly absorbs digest food molecules and water into the bloodstream
Structure of Villi
- Finger-like projections that increase surface area of the small intestine
- Cell membrane of cell lining surface are microvilli
- Epithelium is outside lining of villus
- Lacteal on inside - absorbs Fays into the lymphatic system
- Fluid passes into blood in circulatory system
- Capillaries wrapped around lacteal to increase absorption efficiency
