Organisation Flashcards
What is a tissue?
A tissue is a group of similar cells that work together to carry out a particular function
Examples of tissues
Muscular tissue - contracts to move whatever it’s attached to
Glandular tissue - makes and secretes chemicals like enzymes and hormones
Epithelial tissue - covers some parts of the human body e.g. the inside of the gut
What is an organ system?
An organ system is a group of organs working together to carry out a particular function
Example of an organ system
Digestive system - glands (pancreas and salivary glands) stomach, liver, small intestine and large intestine
Why can enzymes be described as biological catalysts?
They speed up useful chemical reactions in the body
Why do enzymes only usually catalyse one reaction?
Their active site is only complimentary to one type of substrate
What does it mean when an enzyme is denatured?
Its active site has changed shape due to intense heat or acidic conditions
Where is amylase found?
It’s made in the salivary gland and the pancreas and it works in the small intestine
What is the role of lipases?
They break down lipids into fatty acids and glycerol
Where is bile made and stored?
It’s made in the liver and stored in the gall bladder
What does bile do?
It emulsifies fats into smaller, more soluble pieces which gives the fat a bigger surface area for lipase to work on. It also neutralises the stomach acid to make the conditions alkaline, therefore the enzymes can work in the small intestine
What are organs?
Organs are groups of tissues that work together to perform certain functions
What are the tissues in the stomach and what do they do?
Muscular tissue - moves the stomach wall to churn up the food
Glandular tissue - makes digestive juices to digest food
Epithelial tissue - covers the inside and outside of the stomach
What is the name of the substance when a substrate fits into the enzyme’s active site?
Enzyme substrate complex
What is the name of the substance when the enzyme’s active site has turned the substrate into two products?
Enzyme product complex
What is the optimum pH for enzymes?
The pH level that they are most active at. E.g., pepsin has an optimum pH of 2
What does amylase break down?
It catalyses the breakdown of starch to maltose
What do carbohydrases break down?
Carbohydrates into simple sugars
What do proteases break down?
Proteins into amino acids
Where are proteases found?
They’re made in the stomach (called pepsin here) and the pancreas and found in the small intestine
Where are lipases found?
They’re made in the pancreas and work in the small intestine
Name three substances and what they test for
Benedict’s Test - testing for sugars - goes red
Iodine solution - tests for starch - goes blue-black
Biuret Test - tests for proteins - goes purple
What do the salivary glands do?
They produce amylase in the saliva
What does the stomach do?
-It pummels the food with its muscular walls
-It produces pepsin
-It produces hydrochloric acid to kill bacteria and give the right pH for pepsin to work
What does the pancreas do?
It produces amylase
What does the small intestine do?
It contains protease
What does the rectum do?
It stores faeces
What does the large intestine do?
It’s where excess water is absorbed from the food
What does the gall bladder do?
It stores bile before it’s released into the small intestine
What does the liver do?
It produces bile which neutralises stomach acid and emulsifies fat
Where are the lungs?
The thorax
What are the lungs surrounded by?
Pleural membrane
What protects the lungs?
The ribcage
What goes down the trachea?
The air that you breathe in
What tubes join onto the trachea?
The bronchi
What do the bronchi split off into?
Bronchioles
What are the small bags at the end of bronchioles called?
Alveoli
What happens in an alveolus?
Gas exchange. The blood passing next to the alveoli contains lots of carbon dioxide and little oxygen.
The oxygen diffuses out of the alveoli (high concentration) and into the blood (low concentration) and the carbon dioxide diffuses out of the blood (high concentration) and into the alveoli (low concentration) to be breathed out.
What surrounds the alveoli?
Lots of blood capillaries
What happens when blood reaches body cells?
Oxygen is released from the red blood cells and diffuses into the body cells. At the same time, carbon dioxide diffuses out of the body cells and into the blood. It’s then carried back to the heart
What makes up the circulatory system?
The heart, blood vessels and blood
What happens on the right side of the heart?
Deoxygenated blood flows in through the vena cava and into the right atrium. The atrium contracts and pushes the blood through the tricuspid valve, into the right ventricle. The valve closes and the ventricle contracts, to push the blood through the right semi-lunar valve. The valve will close and the blood is pushed out of the pulmonary artery to go up to the lungs
What happens on the left side of the heart?
Oxygenated blood flows in through the pulmonary vein and into the left atrium. The atrium contracts and pushes the blood through the bicuspid valve, into the left ventricle. The valve closes and the ventricle contracts to push the blood through the left semi-lunar valve. The valve will then close and the blood flows out of the aorta to all the cells in the body for gas exchange
How does the heart pump blood around the body?
Blood flows into the two atria from the vena cava (right atrium) and the pulmonary vein (left atrium). The atria contract, pushing the blood into the ventricles through valves. The ventricles contract and force the blood through more valves into the pulmonary artery (right ventricle) and the aorta (left ventricle) and out of the heart
What are the three types of blood vessels?
Arteries, capillaries and veins
What do arteries do?
-They carry blood under high amounts of pressure
-Their walls are strong, elastic and thick
-They have the smallest lumens
-They contain thick layers of muscle to make them strong and elastic fibres to allow them to stretch and spring back
What do capillaries do?
-Arteries branch into capillaries
-They are really tiny - too small to see
-They carry blood really close to every cell in the body to exchange substances with them
-They have permeable walls - substances can diffuse in and out
-They supply food and oxygen and take away waste like carbon dioxide
-Their walls are one cell thick - this increases the rate of diffusion
What do veins do?
-Capillaries join up to form veins
-The blood is at low pressure in the veins so the walls aren’t as thick as an artery’s
-They have the biggest lumen to help the blood flow despite the lower pressure
-They have valves to help keep the blood flowing in the right direction
What is the rate of blood flow?
Volume of blood divided by the number of minutes
What are the four components of blood?
Red blood cells, white blood cells, platelets and plasma
What do red blood cells do?
-They carry oxygen from the lungs to all the cells in the body
-They have a biconcave disc shape - creates a large surface area and allows them to fit through capillaries
-They have no nucleus - can store even more oxygen
-They contain haemoglobin - this binds to oxygen to form oxyhaemoglobin
What do white blood cells do?
-They can change shape to ingest microbes - this process is phagocytosis
-Others produce antibodies to fight microbes
-Some produce antitoxins to neutralise any toxins produced by the microbes
-They have a nucleus
What do platelets do?
-They are small fragments of cells that have no nucleus
-They help the blood to clot at a wound - stops blood pouring out and microbes getting into your bloodstream
-Lack of platelets can cause excessive bleeding and bruising
What does plasma do?
Plasma carries:
-red blood cells
-white blood cells
-glucose
-amino acids
-carbon dioxide
-urea
-hormones
-proteins
-antibodies
-antitoxins
What are stents?
-Tubes that are inserted inside arteries to keep them open which allows the blood to pass through to the heart muscles
-They lower the risk of a heart attack in people with coronary heart disease
-They are effective for a long time
-There is a risk of infection from surgery and the patient could develop a blood clot near the stent - thrombosis
What are statins?
-Drugs that reduce the amount of bad cholesterol (LDL) in your bloodstream
-They slow down the rate of fatty deposits forming
-They reduce the risk of strokes, coronary heart disease and heart attacks
-They increase the amount of good cholesterol (HDL) in your bloodstream - HDL removes LDL from the blood
-They are a long-term drug that must be taken regularly - could be forgotten to be taken
-They can have some negative side effects e.g. headaches, kidney failure, liver damage and memory loss
-It takes time for them to kick in
How does coronary heart disease occur?
The coronary arteries are blocked by layers of fatty material building up. It causes the arteries to narrow therefore the blood flow is restricted and there’s a lack of oxygen to the heart - can result in a heart attack
What are artificial hearts used for?
-If heart donor organs aren’t available or suitable, they are used instead
-They are mechanical devices that pump blood around the body if someone’s heart has failed
-They’re usually temporary to allow someone’s heart to rest and heal
-They’re made from metal or plastic, therefore, they’re less likely to be rejected by the body’s immune system
-Surgery to fit one can cause bleeding and infection
-They don’t work as well as healthy natural ones
-Blood doesn’t flow through them smoothly which can cause blood clots which leads to strokes
What are artificial heart valves used for?
-If heart valves become damaged or weakened by heart attacks, infection or old age they can stiffen up or become leaky
-Artificial heart valves replace the natural valves - they can either be mechanical or taken from a cow or a pig
-It’s less drastic than a heart transplant
-It still takes major surgery and there can be a problem with blood clotting
What is artificial blood used for?
-It’s a blood substitute (e.g. a salt solution) which can replace a large lost volume of blood
-It’s safe and can generally keep people alive no matter how big the blood loss
-It gives the patient time to develop new blood cells or time to wait for a blood transfusion
