Biology-term 3 Flashcards
What is the heart responsible for?
The heart is a muscular pump that is responsible for moving blood throughout the circulatory system.
What is the outer layer of the heart and what does it consist of?
The outer layer of the heart is the pericardium and consists of two layers, the outer fibrous pericardium and inner serous pericardium.
What does the fibrous pericardium consist of?
It protects the heart
What does the serous pericardium consist of?
It contains an inner layer which forms a sac called the myocardium
What is the myocardium>
The thickest layer of heart tissue and a cardiac muscle
What are capillaries?
Fine channels with thin walls that allow for exchange of substances.
What is blood specialised for?
transport and defence
What is the role of blood in homeostasis?
- Transportation
- Regulation
- Defence
What are the components of blood?
Red blood cells, platelets, white blood cells.
What does blood carry?
Oxygen, nutrients and other essential compounds ti every living cell in the body.
Where in the blood is oxygen carried?
By the haemoglobin in the red blood cells
What is bloods relationship with waste products?
takes away from cells, transports hormones, white blood cells and platelets.
What does the blood regulate?
Regulates body temperature and fluid contents
What happens in the blood when the bodies dehydrated?
The plasma will leave the blood ti help maintain body fluid levels. But will absorb fluid if the body is saturated
What are platelets?
An important component of defence and provide the clotting factors found in blood
What is the purpose of the epithelial tissue in the small intestine?
Ridges and folds to increase surface area
What is the primary function of the digestive system?
To transfer nutrients, water and electrolytes from food into the animal bodies internal environment.
Why is ingested food essential?
Its an essential energy source from which the cells can produce ATP to carry out their particular energy-depended activities, such as active transport.
What are the main stages of food processing?
- Ingestion
- Digestion
- Absorption
- Elimination
What does respiration require?
The effective movement of air into and out of the lungs at an appropriate rate and volume to meet the body’s need at any particular time.
What does the upper respiratory tract consist of?
- The nostrils
- Nasal pharynx
- Pharynx (throat)
- Larynx (voice box)
- Trachea (windpipe)
What does the lower respiratory tract do?
Connects the lungs to the vascular system (blood)
What are the alveoli?
Tiny, thin walled sacs that are surrounded by networks of capillaries.
What happens when air is inhaled?
Oxygen moves through the upper respiratory system to eventually reach the alveoli, where it crosses the alveoli and capillary membranes into the blood system - at the same time, carbon dioxide moves from the bloodstream across the membranes into the alveoli, through the lungs and is exhaled.
What is excretion?
the movement of toxic materials, water, products of metabolism and excess materials from the body.
Why is excretion necessary?
To rid the body of waste products and to regulate volume and composition of body fluids.
What is metabolism?
The chemical process going on in the body to allow normal body functions.
What is the one type of waste that is not excreted by the body?
Faeces, which are egested.
What materials are excreted from the body?
- carbon dioxide
- Urea
- excess water
- Ions (Na, K, Cl)
- vitamins
- toxins
How is urea produced?
Produced when excess proteins and amino acids are broken down in the liver.
Why are the kidneys vital organs?
Part of the urinary system and are the main organ responsible for filtering the blood and excreting wastes.
What does the urinary system consist of?
- Right and left kidney
- Right and left ureters
- Urinary bladder
- Uretha
What is the outer portion of the kidney called?
The renal cortex
What is the inner portion of the kidney called?
The renal medulla
What is the hilus?
Where blood, nerves and ureters enter the kidney.
What is the renal pelvis?
Funnel shaped area after the hilus
What are the calyces?
Extensions of the renal pelvis which lead onto the medulla.
What are nephrons?
Hundreds of thousands of microscopic, filtering, reabsorbing and excreting systems.
What are the eight main structures in the nephron?
- Afferent renal artery
- Glomerulus
- Bowman’s capsule
- Efferent renal artery
- Proximal convoluted tubule (first coiled tubule)
- Loop of henle
- Distal convoluted tubule (second coiled tubule)
- Collecting duct
What is the main functions of the kidney?
Excreting waste in the form of urine and maintaining water balance.
Through which processes do the kidneys undertake for their main functions?
- Filtration
- Reabsorbtion
- Excretion
In the kidney, which substances are filtered, reabsorbed or excreted?
blood is filtered, useful substances are reabsorbed into circulation and waste products are excreted in the form of urine.
What is the simple explanation of how the kidney works?
Blood enter the kidney from the renal artery–> Nephron (the filter) –> Filtered blood leaves the kidney through renal vein –> urine leaves kidney through ureter.
READ DEEPER EXPLANATION
Glycogen:
a stored from of polysaccharide (carbohydrate), which on hydolysis forms glucose
Hydrolysis:
Chemical breakdown of a compound with the addition of water.
Emulsification:
the breakdown of fat globules in the duodenum into tiny droplets, which provides a larger surface area on which the pancreatic lipase can act to digest fats into fatty acids and glycerol.
Toxin:
a poison of plant or animal origin
What does the liver consist of?
Two main lobes, the left of which is smaller than the right
What takes blood to and from the liver?
Hepatic artery = to the liver, portal vein = out of liver.
What does the common bile duct carry?
Carries bile from the liver via the hepatic and cystic ducts to the gallbladder
How is the liver associated with bile?
Produces bile, which is then secreted through the common bile duct into the gallbladder, which is then released into the duodenum for the emulsification of fats.
How is the liver associated with proteins?
Produces proteins, e.g. albumin - a protein needed for the blood.
How is the liver associated with sugar levels?
Regulates sugar levels in the blood; stores glycogen and releases glucose as required.
How is the liver involved with toxins?
Removes toxins, poisons, old RC and other harmful agents.
What happens when the liver has broken down harmful substances?
They are excreted into the blood or bile, leaving the body in faeces or filtered out by the kidneys in urine.
Where are majority of nutrients absorbed into the bloodstream?
The small intestine
What are the three segments of the small intestine?
- Duodenum
- Jejenum
- Ileum
What is the duodenum?
The first, short segment that leaves the stomach
What is the Jejenum?
The largest portion of the small intestine
What is the ileum?
Its short and enters the colon (large intestine)
What is ingestion?
The act of eating and the first stage of food processing
What is the role of teeth in digestion?
Various shapes-cut, smash and grind food, making it easier to swallow and increasing its surface area.
What does the presence of food do to the oral cavity?
It triggers a nervous reflex that causes the salivary glands to deliver saliva through ducts to the oral cavity.
What is much?
A slippery glycoprotein contained in saliva
What does much do?
It protects the lining of the mouth from abrasions and lubricates food for easier swallowing
What are the three salivary glands?
Parotid gland, sublingual gland and submandibular gland.
In the lower and upper arcade, the incisor teeth are the most what?
Rostral
Where are the canines located?
At the corners of the incisors.
What features are typical of canines?
Typically longer than other teeth and can have a pointed tip
What are the premolars?
The rostral cheek teeth and can have some sharp tips
What are the molars?
The caudal cheek teeth and have large flat surfaces.
What is the function of the upper palate?
Allows breathing and chewing or sucking to take place simultaneously
What is the hard palate made from?
Bone
What is the soft palate made of?
Connective tissue
What does the tongue mostly consist of?
Voluntarily controlled skeletal muscle
What are the five areas of the stomach?
- Cardia
- Fundus
- Body
- Pyloric antrum
- Pylorus
Where is the cardia?
Immediately surrounds the opening from the oesophagus
What does the fundus form?
Forms a distensible, blind pouch that expands as more food is swallowed.
What is the body of the stomach?
A distensible section in the middle of the stomach
What is the fundus and body of stomach rich with?
Glands
What are the three glands in the stomach?
- Parietal cells > Hydrochloric acid
- Chief cells > pepsinogen
- Mucous cells > Protective mucous
What is the pyloric antrum?
The distal part of the stomach that grinds up swallowed food and regulates the hydrochloric acid that is produced.
What do the G cells in the pyloric antrum do?
Secrete the hormone gastrin
What does the plyorus do?
Regulates the movement of chyme and prevents back flow from the duodenum.
What is chyme?
A thick mixture of food and gastric fluid with a high acidity
How is it mixed and moved?
by peristalsis
What does swallowing do?
Stimulates vigorous mixing, grinding and propulsive contractions that move food towards the pylorus
