Monday 3 September 2012

Nutrient and Digestive System

What nutrients do we need?

Organic Nutrients (obtained from living organisms, are all compounds of carbon)
  • Carbohydrates
  • Lipids
  • Proteins
  • Vitamins
  • Dietary Fibre
Inorganic Nutrients
  • Water
  • Mineral salts

Carbohydrates

-Organic compounds that are made up of C, H & O.












For example...













Lipids (fat)

*But there is a difference between lipids and fats.

Hydrolysis of a Fat Molecule












Proteins

-Made up of amino acids of which there are 20 naturally occurring types.


















Functions of Proteins
-Essential for the synthesis of protoplasm, for growth and repair of worn out cells.
-Synthesis of enzymes and hormones
-Formation of antibodies to combat diseases
-Source of energy (17KJ/g)

Malnutrition: The consequences of deficiencies

Kwashiorkor - Lack of protein
Kwashiorkor is an African word meaning the disease the first child gets when the second is born or the 'disease of the first child gets when the second is born or the disease of the deposed child'

Symptoms:
-Greying hair
-Swelling of the abdomen
-Skin crack and become scaly

Deficiency in Vitamins

Vitamin A
Signs of deficiency: Poor night vision or night blindness, loss of appetite, increased susceptibility to infection, and changes in the skin and teeth

Vitamin E
Signs of deficiency: *Anemia in infants and nerve damage in adults.
*decrease in the red blood cells

Vitamin K
Signs of deficiency: Excessive bleeding and an inability for blood to clot

Vitamin C
Signs of deficiency: black-and-blue marks, bleeding gums, nose bleeds and wounds that heal slower than normal. Swollen, tender joints and aching bones, general weakness, loss of appetite and dry, scaly skin.
->> Scurvy (deficiency in Vitamin C)
       - painful, swollen joints
       -Swollen, bleeding gums; loss of teeth

Vitamin D
Signs of deficiency: A prolonged lack of this nutrient results in changes in the bones of children and adults.

Minerals
-Calcium
->> Rickets- deficiency in Vitamin D or Calcium
(bow-legged; bending of legs)

-Iron
Deficiency causes anaemia.

Other deficiencies
-Iodine deficiency is the main cause of potentially preventable mental retardation in childhood , as well as causing goitre and hypothyroidism in people of all ages.
-Iron deficiency may lead to anemia and eventually fatigue.

Mammalian Transport System - Part 3

Learning Objectives

  • Learn about the structure and function of arteries, veins and capillaries. 
  • Compare and contrast the structure of arteries and veins, and state how they are adapted for its function.
  • Learn about the components of blood.
  • Understanding blood pressure.

From very big vessels, blood flows at a very fast rate. When it goes to the smaller vessels, extremely slow.(capillary)

Capillary, Arteriole, venule -----> no muscles

Functional Comparison Between Arteries & Veins

Arteries
-Transport blood away from the heart
-Transports blood under higher pressure (than veins)
-Carry oxygenated blood (except in the case of the pulmonary artery)

Veins                                                             

-Transports blood towards the heart              
-Transports blood under lower pressure (than arteries)      
-Carry de-oxygenated blood (except in the case of the pulmonary vein) 

Structural Comparison Between Arteries & Veins

Arteries
-Have relatively more muscle/ elastic tissue; 
-Have relatively narrow lumens
-Do not have valves (except for the semi-luna valves of the pulmonary artery and theaorta)

Veins
-Have relatively less muscle/elastic tissue
-Have relatively wider lumens
-Have valve throughout the main veins of the body. These are to prevent blood flowing in the wrong direction, as this could (in theory) return waste materials to the tissues.




                                                            


Mammalian Transport System- Part 1

Human Circulatory System

Consist of 

1. Cardiovascular System                        2. Lymphatic System
  • Made up of
         -Heart 
         -Blood vessels
         -Blood

Cardiovascular System

  1. Blood - The main 'transportation service' that handles the distribution of nutrients, oxygen and hormones to the various regions of the body.
  2. Arteries & Veins - A system of tubes that form the transport route where blood flows. 
  3. Heart - The motor of this transport service.
  4. Capillaries - are sites of exchange

Human Cardiovascular System 

  • Divided into :
          1.Pulmonary System & Heart
              -Pulmonary = lungs
         
          2. Coronary System 
              -Coronary = heart
         
          3. Systemic Circulation
              -Systemic= rest of body