Human nutrition & Excretion

anabolic reaction

a metabolic process that involves synthesis of 2 substrates that form 1 larger molecule

Reabsorption

useful molecules are recovered from filtrate after filtration of blood ( water, salt, amino acids )

Absorption

the movement of nutrients from the intestines to the blood

what

what is the role of the small intestine during digestion

Absorption - food is moving from the alimentary canal into the blood (water is also absorbed)

Nutrients are absorbed

Catabolic reaction

1 substrate that forms 2 smaller molecules

what is the role of chemical digestion

breaking down insoluble molecules into soluble molecules using enzymes so that the products can be absorbed

ingestion

the consumption of food happens in the mouth

egestion

the removal of undigested food from the body as feces- passed through anus

why is the villi important

they increase the surface area for food absorption and adding digestive secretions

what happens when an enzyme denatures

shape of the active site changes so it can no longer fit in the substrate, the function, the enzyme can’t act as a biological catalyst anymore

describe chemical digestion

the breakdown of large insoluble molecules into small soluble molecules happens in the stomach

balanced diet

a diet containing the right food and minerals and minerals and the right amounts

amylase breaks down what? and where is it found

found in the mouth and ileum, breaks down starch into maltose

lipase breaks down what and where is it found

found in the stomach, breaks down fats into fatty acids and glycerol

maltase breaks down what and where is it found

found in the ileum breaks down maltose into glucose

what factors impact enzyme activity

temperature

pH

concentration of substrate (substance on which enzyme acts)

physical digestion

increases the surface area of food ( by chewing ) for the action of enzymes in chemical digestion

Where are the villi found

in the duodenum in the small intestine

causes of:

1) scurvy

2) rickets

1) lack of vitamin C

2) lack of vitamin D

parts of the digestive system

mouth

esophagous

stomach

small intestine

pancreas

liver

gallbladder

large intestine

rectum

anus

function of stomach in physical digestion

the stomach has muscular contractions which mix the ingested food with gastric juices and producing chyme. The stomach contains HCl, amylase, pancreatic juice, bile

What do goblet cells do in the villi

produce mucus to protect the villi from any acids in chyme

principal dietary sources

carbohydrates

fats and oils

proteins

vitamins

mineral ions

fibre

water

what is urea

a waste product formed by the breakdown of protein in the liver, the kidney filters urea out of the blood and into the urine

what s the role of bile

bile is produced in the liver and breaks down fats and lipids

Fats fatty acids and glycerol - emulsification

Bile is stored in the gall bladder

what is physical digestion

the breakdown of food into smaller pieces without chemical change to the food molecules

protease breaks down what and where is it found

proteins into amino acids found in the intestines

pepsin breaks down what and where is it found

breaks down proteins into peptides found in the stomach

what is assimilation

the uptake and use of nutrients by cells used for energy growth and repair

describe denimation

in the liver an excess group of amino acids is turned into ammonia which is toxic so it is turned into urea which is filtered in the kidney and excreted as urine

what does the lacteal in the villi absorb

digested lipids ( fatty acids and glycerol )

what is bile

bile is an alkaline mixture that neutralises the acidic mixture of food and gastric juices entering the duodenum from the stomach to provide a suitable pH for enzymes

why is emulsification important

because it increases the surface area so that enzymes can break down the fats ( lipase) ensuring fats can be digested and absorbed efficiently

what do the capillaries of the villi absorb during digestion

they absorb glucose and amino acids

what do micro villi do

increase surface area

1) temp

2) pH

3) substrate conc

what are the parts of the teeth

enamel ( the top )

dentine ( hardest layer )

pulp cavity ( the inside )

nerves ( inside pulp cavity )

blood vessels ( bottom )

cement ( outer layer )

what are the 4 types of teeth

premolar

molar

incisor

canine

function of molar and premolar

to grind the food

function of incisor and canine

to cut the food

enamel

dentine

pulp cavity

nerves

cement

blood capillaries

jaw bone

gums

function of vitamin A

vision, skin, growth

function of vitamin C

tissue growth, wound healing, immune system

what is the fuction of vitamin D

bone health, nerves, muscles

vitaminnE function

immune system, antioxidant

active transport

the movement of molecules across a cell membrane from a low to high concentration

passive transport

the movement of substances accross a cell membrane from high concentration to low concentration

what are the parts of the kidney

nephron

glomerulus

bowman’s capsule

medulla

renal cortex

renal pyramids

urethra

renal arteries and veins

what are 2 roles of the nephrons in the kidney

1) filtration

2) reabsorption

DCT & role

distilled convoluted tubule - reabsorption of nutrients

PCT & role in nephron & transport

proximal convoluted tubule - reabsorption of glucose amino acids, water and salt ( passive and active transport )

glomerulus role in nephron & function

filters blood - passive transport

henles loop role in nephron & transport

reabsorption of water and salt - passive and active transport

collecting duct role in nephron & transport

reabsorption of water - controlled by adh

bowmans capsule role in nephron and transport

filters blood from glomerulus - passive transport