EAC The Digestive System Flashcards
3 basic food groups
Carbohydrates
Proteins
Fats
in addition minerals and vitamins are also absorbed
how are the basic food groups used by the body?
to build and repair the body
as fuel to produce heat and energy
to provide raw materials for the body’s chemical activities
to help maintain health
4 stages of the digestive process
Ingestion
Digestion
Absorption
Elimination
define:
Ingestion
food is taken into the alimentary tract
define:
Digestion
food is broken down mechanically by chewing and chemically by enzymes secreted by glands in the digestive system.
define:
Enzyme
a chemical substance which causes, or accelerates, a chemical change in another substance without being changed itself
define:
Absorption
food which has been digested passes through the walls of some organs of the alimentary tract into the bloodstream to be used by the body tissues
define:
Elimination
Undigested components of food are excreted from the bowel as faeces
define:
Peristalsis
rhythmic muscular contraction of the walls of the tract which pushes the food through in one direction. This involuntary action is known as peristalsis
Components of the Digestive System
Digestive processes:
Mechanical process - chewing
Chemical Process - saliva, stomach acid
Alimentary Tract or Cana/Gastro-Intestinal/GI tract: Actively transports the flow of food through the whole of the digestive process
Accessory organs of digestion: these organs produce some of the chemicals necessary for digestion and include; salivary glands, liver, gall bladder, pancreas
Function of Digestion
The digestive system is made up of organs which convert solid and liquid foods into forms of essential, basic nutrients which the body tissues can use
It also helps to remove the bodies waste products
define:
Mouth
also referred to as the oral or buccal cavity
Tongue
Teeth
3 pairs of salivary glands: parotid, sub-lingual and sub-mandibular
define:
Pharynx
pharynx or throat is an expanded muscular tube lying behind the nose and mouth
shared with the respiratory tract
divided into 3 parts:
Nasopharynx
Oropharynx
Laryngopharynx
define:
Epiglottis
A leaf-shaped plate of yellow fibro-elastic cartilage located at the entrance of the larynx
its main function is to prevent food entering the larynx during the act of swallowing
define:
Oesophagus
oesophagus or gullet is a collapsable, muscular tube
descends form the pharynx above to the cardiac orifice of the stomach below
approx. 25cm long
movement of a food bolus along it is by peristalsis action
smooth muscle, elastic tissue and mucous membrane
define:
Stomach
muscular bag like organ
walls are lined with mucous membrane
contains the cardiac sphincter at its connection with the oesophagus which helps prevent regurgitation
is able to contract in a variety of ways to help churn up food. this helps mix food with gastric juices containing hydrochloric acid, water and enzyme
chyme is produced which then passes into the duodenum via the pyloric sphincter, which helps prevent regurgitation back into the stomach
define:
Duodenum
first part of the small intestine
25cm long
both bile duct and pancreatic duct (endocrine glands) empty into the duodenum
bile, pancreatic and intestinal juices complete the conversion of chyme into amino acids
define:
Small Intestine
6 metres long
Muscular tube lined with connective tissue and mucous membrane
Comprises of the duodenum, jejunum and ileum
Continuos with the duodenum above and the large intestine below
outer covering is formed by the peritoneum
large surface area for digestion and absorption
Nutrients pass through the inner lining and are absorbed by blood vessels contained in the wall of the intestine
define:
Large intestine/Colon
1.5 metres long
absorbs water
absorbs electrolytes, vitamins
storage of faecal material
expulsion of faeces
synthesis of vitamins K, B by using symbiotic bacteria
divisions of the Large Intestine/Colon
Caecum Vermiform appendix ascending colon transverse colon descending colon sigmoid colon rectum anus
define:
Peritoneum
serous membrane that lines the abdominal cavity
covers abdominal organs
prevents friction
helps hold the organs in position
carries blood vessels that help fight infection
functions of:
Liver
generates heat carbohydrate, lipid and protein metabolism Processing of drugs and hormones excretion of bilirubin synthesis of bile salts storage for vitamins and minerals phagocytosis - RBC's, WBC's and some bacteria Activation of vitamin D
functions of:
Pancreas
oblong in shape
dual function organ
12-15cm long
connected to the duodenum by 2 ducts
secretes pancreatic juices (enzymes)
secretes insulin and glucagon (hormones)
function of: Gall Bladder
stores and concentrates bile
releases bile into the small intestine
function of: Kidneys
filters blood to help remove waste products
regulates acid base balance and pH of the blood
regulates blood volume
regulates blood pressure
regulates salt water balance
produces hormones
regulation of blood glucose levels
excretes urine: urine contains the end products of metabolism, drugs, toxins and other harmful chemical substances
function of: Ureters
two fine tubes 25-30cm long
they pass from the kidneys to the bladder
they carry urine
function of: Bladder
the bladder is a muscular bag
it acts as a reservoir for urine passed via the ureters from the kidneys
it lies behind the pubis in the pelvic cavity
it normally holds 300ml
maximum capacity 800ml (smaller in women)
when full it rises up into the abdominal cavity
function of: Urethra
urine is passed form the bladder via the urethra in the penis and vagina during the act of Micturition
the canal leading from the bladder to the outside of the body
define:
Uterus
positioned in the centre of the pelvic cavity
lies between the bladder and rectum
two uterine tubes (fallopian tubes) connect the ovaries to the uterus
define:
Ovaries
2 small glands about the size and shape of an almond
they produce the female ova
ova are released into these uterine tubes, moving on to the uterus where they are either fertilised or passed out from the body during the menstrual cycle
be able to label…
digestive system diagram
Male/female genital diagram
relationship between Digestive System, circulatory system, respiratory and renal system
DS breaks food down into energy used with oxygen intake from RS and water from DS/RS to make ATP in cells that they use to function. the CV system uses ATP to function and pump blood around the body allowing it to collect nutrients, oxygen and water.
Waste products are filtered and eliminated by the Renal System
