Unit 7 Human nutrition

- What are nutrients divided into?

Macronutrients and micronutrients

- What are macronutrients?

food substances eaten in large amounts eg:protein, carbohydrates, fats

- What are micronutrients?

Food substances eaten in smaller amounts eg:vitamins and minerals

- What should a balanced diet include?

energy provided by protein carbs etc, amino acids from proteins, fatty acids from fats, micronutrients- vitamins minerals, water to replace water lost in urine, sweat, fibre to move food from mouth to anus

- What are the suggested portions of foods recommended?

fruit and vegetable- 5 portions a day, starchy carbohydrates- 3-4 portions a day, beans, pulses, fish, eggs, meat, proteins- 2-3 portions a day, Dairy and alternatives- 2-3 portions a day

- Why are nutrients important?

To provide energy- provided by carbohydrates and fats, and proteins only used for energy when had in excess amounts. To allow growth and repair- Proteins provide a source of amino acids for cells to make their own proteins, Regulating the body's metabolism- vitamins and minerals needed to regulate the body metabolism

- How is the body still using energy despite not being active?

The body still uses energy to keep the heart beating, lungs working and body temperature constant

- Why do young children have a greater basal metabolic rate?

They are still growing and therefore need the energy

- Explain carbohydrates

Carbohydrates include sugars and starches providing the body with a source of energy that can be respired quickly by the stomach into the blood as an immediate source of energy.

- Explain proteins

Protein is important so that the body can grow and develop, protein is digested into 20 amino acids which makes more proteins. Protein is needed to replace old or damage cells, if protein is not needed for growth it can be respired to provide energy. eg-milk, meat, fish, nuts

- Explain fats

Long term energy store, when the body is short of energy it uses fat, fats are good thermal insulators

- Explain the necessity of water in the body

Water is necessary so chemical reactions can take place in solution, blood transports substances dissolved in water

- Explain the necessity of vitamins and minerals in the body

vitamins are essential to avoid developing deficiency diseases in the body

- Name a rich food source of Vitamin C

Oranges, lemon, citrus fruits

- What is vitamin C used for in the body

helps bond cells together, aids in the use of calcium by bones and teeth, vitamin C is used to form an important protein that helps to make skin, tendons, ligaments and blood vessels, healing of wounds and scar tissue

- Name Deficiency diseases of Vitamin C

bleeding gums (scurvy)

- Name a rich food source of Vitamin D

fish oil, milk, butter

- What is vitamin D used for in the body

needed for small intestine to absorb calcium, regulates the deposition of calcium in bones

- Name deficiency diseases of vitamin D

rickets in children, osteomalacia in adults

- Name a rich food source of iron

liver, meat, cocao, eggs

- What is iron used for in the body

formation of haemoglobin in RBC for transport of oxygen

- Name deficiency diseases of iron

lack of iron leads to reduces no. of RBC's in the body, causing anaemia (symptoms- tiredness, lack of energy, shortness of breath, heart palpatations, pale complexion)

- Name a rich food source of calcium

milk, fish, green vegetables

- What is calcium used for in the body

deposited in bones and teeth as calcium phosphate (making them hard), present in blood plasma- helps in blood clotting, involved in chemical reaction that enables muscle contraction and transmission of nerve impulses

- Name deficiency diseases of calcium

weak, brittle bones and teeth (rickets), muscle weakening, cramps

- Explain the necessity of fibres in the body

made up of cellulose from plant walls- the muscles in the gut wall need something to push against, fibre helps the movement of the food in the alimentary canal by peristalsis preventing constipation. Fibre absorbs poisoning waste killing bacteria in our gut lowering the risk of cholesterol, risk of heart disease, bowel cancer

- Name similarities of all vitamins

* Imp in small quantities
* able to work with enzymes to control chemical reactions in the body

- What can vitamins not do

Be digested or broken down by enzymes, be used to build body structures

- What is ingestion

taking in of substances (food and drink) into the body through the mouth

- What is digestion

breaking down of large insoluble molecules into smaller soluble molecules so they can pass through the gut wall into the blood

- What is absorption

movement of small molecules and ions through the wall of intestine into the blood

- What is egestion

passing out of food that has not been digested

- What is physical digestion

breakdown of large pieces of food into smaller pieces without changing the food molecules. Chewing in the mouth where food gets broken down, muscular contractions of stomach, emulsification of bile in small intestine. Increases surface area which makes it easier for enzymes to catalyse the reactions needed for chemical digestion.

- What is chemical digestion

breakdown of large insoluble food molecules into smaller soluble molecules by enzymes.

- What are the three types of enzymes in the ailementary canal

protease, carbohydrase⇒amylase, lipase

- What do protease enzymes do?

Break down proteins and polypeptides to peptides ⇒ Name- trypsin

- What do amylase enzymes do?

breaks down starch to maltose (reducing sugar)

- What do lipase enzymes do?

break down fat molecules and glycerol

- What are the types of teeth in humans and their function and numbers

Incisors⇒chisel shaped for biting and cutting⇒ 8, Canines⇒ pointed for piercing and tearing ⇒4, Premolars⇒ uneven cusps for grinding and chewing ⇒8, Molars⇒ uneven cusps for chewing ⇒12

- What are the gums made up of

composed of soft tissue with many blood vessels and nerves

- What is the enamel

hard, outer layer of the crown of the tooth

- What is the dentine

bone like structure inside enamel

- What is the role of the layer of cement

fixes the root of the tooth into a bone into jaw

- What is the pulp cavity

space in the tooth containing nerves and blood vessels

- How is bolus made

After the tongue mixes food with saliva and moistened food is chewed by the teeth, rolled into a ball or bolus.

- What do the salivary glands contain

Mucus⇒ slimy substance that lubricates the passage of the bolus down the throat , Amylase⇒ enzyme that catalyses the breakdown of starch to maltose

- What is the function of epiglotis

covers the opening of trachea when you swallow

- What is the structure of the oesophagus

has circular and longitudinal muscles in its wall

- What is peristalsis

muscular contraction that moves the food down the oesophagus

- What are the digestive juices in the stomach called and their function

Called gastric juices , Contains protease ⇒starts the digestion of proteins to polypeptides, Contains hydrochloric acid ⇒ has low PH killing any harmful microorganisms in the food, ph levels of 1.5 to 2 optimum for action of protease enzyme

- What do the pyloric sphincters do

opens to let food pass into the duodenum

- What is bile and it's function

Yellow-green fluid made in liver and stored in gallbladder, Alkaline and neutralises acid that was added to the food in stomach⇒ best ph for enzymes in small intestines, Emulsifies fats by breaking large fat globules into small fat globules⇒ larger surface area so lipase can break molecules down into fatty acids and glycerol

- What enzymes do the cells in the ileum make?

Protease⇒ breakdown of peptides to amino acids, Sucrose⇒ breakdown of sucrose to glucose to fructose, maltose⇒ broken down by maltase to glucose on the membrane of epithelial lining of small intestine.

- What is absorption

movement of digested food molecules through the wall of intestine into blood or lymph.

- What are the adaptations of small intestine for efficient absorption?

large surface area ⇒ 9 sq metres, a thin lining so digested food can cross easily to the blood

- What are villi?

folded inner lining with millions of tiny finger like projections, it's epithilial cell lining have microscopic projections called microvilli.

- How is food digested in the small intestine?

digested food reaches capillaries and lacteals in the villi, absorbed food molecules transported to liver by hepatic portal vein , fatty acids and glycerol transported in the lymph, Lymph moves slowly through lymphatic vessels (like veins) which eventually enter the blood near the heart.