Digestive And Excretory System Flashcards
Define amylase
the crystallizable form of starch, consisting of long unbranched polysaccharide chains
Define Anus
the opening at the end of the alimentary canal through which solid waste matter leaves the body.
Define bile
a bitter greenish-brown alkaline fluid which aids digestion and is secreted by the liver and stored in the gall bladder.
Define carbohydrates
Mainly sugars and starches, together constituting one of the three principal types of nutrients used as energy sources (calories) by the body.
Carbohydrates can also be defined chemically as neutral compounds of carbon, hydrogen and oxygen.
Define deamination
The removal of amino group from an amino acid molecule
Define defecation
The discharge of faeces from the body
Define digestion
The mechanical and chemical breakdown of food to small molecules that can be absorbed into the body
Define enzyme
Proteins that speeds up the rate of a chemical reaction in a living organism.
Without enzymes, life as we know it would not exist.
Define fatty acids
a carboxylic acid consisting of a hydrocarbon chain and a terminal carboxyl group, especially any of those occurring as esters in fats and oils.
Define gall bladder
small sac-shaped organ
beneath the liver
bile is stored after secretion by the liver and
before release into the intestine.
Define large intestine
The part of the intestine between the small intestine and the anus.
It is made up of caecum, colon and rectum
Define lipid
Large organic molecules made up of fatty acids and glycerol
Define liver
a large lobed glandular organ in the abdomen of vertebrates, involved in many metabolic processes.
Define mastication
Mastication or chewing is the process by which food is crushed and ground by teeth. It is the first step of digestion, and it increases the surface area of foods to allow more efficient break down by enzymes.
Define mouth
the opening and cavity in the lower part of the human face, surrounded by the lips, through which food is taken in and vocal sounds are emitted.
Define oesophagus
The tube that carries food from the throat to the stomach
Define pancreas
a large gland behind the stomach
secretes digestive enzymes into the duodenum.
secrete into the blood the hormones insulin and glucagon.
Define peristalsis
Waves of muscular contraction that pushes food along the alimentary canal
Define protein
A molecule composed of polymers of amino acids joined together by peptide bonds.
Define rectum
the final section of the large intestine, terminating at the anus.
Define saliva
A fluid secreted into the mouth by salivary glands to begin digestion of food
Define secretion
a process by which substances are produced and discharged from a cell, gland, or organ for a particular function in the organism or for excretion.
Define small intestine
The longest part of the alimentary canal, it receives materials from the stomach
Define villi
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Define alimentary canal
The tube via which food passes through the body, consisting of the mouth, oesophagus, stomach and intestines.
Also known as the digestive track.
Define mucosa
A mucosa membrane, in the particular the mucosa membrane that forms the internal lining of the alimentary canal
Define vitamins
any of a group of organic compounds which are essential for normal growth and nutrition and are required in small quantities in the diet because they cannot be synthesized by the body.
Define elimination
The removal of indigestible materials, bacteria and bile pigments from the body
Define excretion
Removal from the body of the waste from metabolism
Define kidney
The principle excretory organ of the human body.
It filters waste from the blood and regulates the balance of water and salts in the blood plasma
Define nephron
The functional unit of the kidney
Define renal pelvis
The cavity of the kidney which collects urine before it passes to the ureter
Define glomerulus
a cluster of nerve endings, spores, or small blood vessels, especially a cluster of capillaries around the end of a kidney tubule.
Define afferent arteriole
The blood vessel that enters an organ
Define efferent arteriole
The blood vessel that leaves a glomerulus in the kidney
Define bowman’s capsule
Bowman’s capsule (or glomerular capsule) is a cup-like sac at the beginning of the tubular component of a nephron in the mammalian kidney that performs the first step in the filtration of blood to form urine. A glomerulus is enclosed in the sac.
Define filtrate
The fluid remaining after filtration has taken place
Define reabsorption
The process by which substances are transported from the filtrate in the renal tubules into the blood of the peritubular capillaries
Define tubular secretion
The process whereby ions and drugs are secreted from the blood into the kidney tubule
Define dialysis
A method of removing waste from the blood when kidney failure occurs
Define absorption
The transfer of a vitamin from the digestive tract to the bloodstream.
Define amino acids
Small molecules that join together to make proteins
List all the nutrient groups that are essential
Carbohydrates Proteins Lipids Vitamins Minerals Water
Sub units of Carbohydrates
monosaccharides,
polysaccharides and
oligosaccharides
Sub units of Proteins
amino acids
Sub units of Lipids
triglycerides,
fats,
glycerol
Describe how the stomach’s structure is related to the function it performs
The stomach is folded up to begin with then as food passes into it it unfolds allowing more food to be taken in.
-the stomach contains small pits around the lining (gastric pits). These contain cells that secrete hydrochloric acid and peptinogen which, in the presence of the acid turns to peptin. This is an enzyme that starts to break down proteins. (its an endopeptidase).
- there are muscles at the entrance and exit of the stomach that allow food to pass in.
- food is mashed up to a substance called chyme by a process called peristalsis which basically means contracting the stomachs muscles to turn the food into a acidic paste. This helps it to be broken down and absorbed in the gut (small and large intestine).
-not sure if this is 100% accurate but i think the stomach contains pressure detecting receptors that trigger the release of the hcl and peptinogen. These are activated when the food passes into the stomach and moves across them.
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Describe how the villi’s structure is related to the function it performs
In addition to increasing surface area, each villus/microvillus has a capillary carrying blood that is low in nutrients. However, the chyme flowing through the small intestine (chyme is the soupy nutrients from the chemically digested food) is high in nutrient molecules as compared to the blood. So, the nutrients diffuse into the blood stream.
From there, via the hepatic artery, the blood flows directly to the liver where toxins are removed before the nutrient rich blood flows to the cells
What is the role of the lacteals in digestion
A lymphatic capillary that absorbs dietary fats in the villi of the small intestine.
Describe how the skin excretes its waste procuct
The skin excretes waste by precipitation or sweating and letting the salts out by opening the pores
Explain how the lungs excrete their waste products
lungs take in oxygen and get rid of carbon dioxide. since the body needs oxygen to live, carbon dioxide is considered waste
The Lungs are made of tiny sacs called pulmonary alveoli(singular form: alveolus). These alveoli are surrounded by tiny capillaries. The waste from the cells of the lungs is transferred into these capillaries by the process of diffusion. The blood in the capillaries then carry the wastes off to the kidney, where it is filtered.
The lungs excretes waste by the body cells and carbon dioxide
Why are lipids used to separate fluids in the body? Eg. In membranes?
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How does the structure of the mouth suit its function
Teeth: mechanical digestion where food is broken down into smaller pieces
Four incisors: bitting or cutting
Two canines: tearing
Four premolars: two on each side
Six molars: broad crowns for crushing and grinding food
Explain the role that the lymphatic system has in the absorption of lipids
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What is mechanical digestion
Involves physically breaking down the food into smaller piece. Happens when food is chewed
What is chemical digestion
Involves breaking down the food into simpler nutrients that can be used by the cells
What is the function of the liver
Production of bile, which helps carry away waste and break down fats in the small intestine during digestion
Production of cholesterol and special proteins to help carry fats through the body
Store and release glucose as needed
Processing of hemoglobin for use of its iron content
Conversion of harmful ammonia to urea
Clearing the blood of drugs and other harmful substances
Regulating blood clotting
Resisting infections by producing immune factors and removing bacteria from the bloodstream
Why is eating a large range of foods important to the functioning of the human body?
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Explain how the kidneys filter materials out of the body
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List the major excretory organs and what they excrete
Kidneys: water, urea and uric acids
Lungs: carbon dioxide, water vapour
Skin: sweat(urine but less concentrated)
Liver: secrete bile (
Livers role in excretion
- conversion of ammonia( a major toxic metabolic nitrogenous product) into urea which is excreted through urine as uric acid .
- Production of bile juices that help in the breakdown of lipid molecules
3 . breaks down haemoglobin and formation of new RBC’s occurs
4.Helps in purifying blood ( HEPATIC PORTAL SYSTEM)
Production of urine: glomerular filtration
Filters water and certain substances from the blood plasma
This increases blood pressure
Forces plasma like fluid into bowman’s capsule
Then into tubules
Production of urine: tubule reabsorption
Substances are transported out of the tubules back into the blood of the peri tubular capillary
Occurs in proximal tubule, loop of Henley, distal tubule
Production of urine: tubule secretion
Substances move from plasma in the peri tubular capillary back into the filtrate in the renal tubules
Proximal tubule secretes: creatine and histamine, hydrogen ions
Distal tubule and collecting duct secrete: potassium, hydrogen ions
Urine composition
96% water
- 0% urea
- 5% various ions
- 5% other
Source of carbohydrates
plants
Food example: starch, sugar, cereal, potatoes, and roots
Function of carbohydrates
providing energy for working muscles,
fuel for the central nervous system,
enabling fat metabolism,
and preventing protein from being used as energy
Functions of proteins
structure of red blood cells,
for the proper functioning of antibodies resisting infection,
for the regulation of enzymes and hormones,
for growth,
and for the repair of body tissue.
Sources of protein
Milk,
Cheese,
Yoghurt,
Red meat
Function or lipids
energy storage and production, insulation and protection, digestion and absorption, cell wall structure, hormone production
