Topic 2- Animal Tissues, Organs and systems Flashcards
What is the main function of the digestive system?
To digest food and absorb the nutrients obtained from digestion
What is the role of the pancreas and the salivary gland in the digestive system?
They are glands which produce digestive juices containing enzymes
What is the role of the stomach in the digestive system
Produces hydrochloric acid- which kills any bacteria present and provided the optimum acidic pH for the protease enzyme to function
What is the role of the small intestine in the digestive system?
The small intestine is the site where soluble food molecules are absorbed into the bloodstream
What is the role of the liver in the digestive system?
Produce bile (stored in the gallbladder) which emulsifies lipids and allows the lipase enzyme to work more efficiently
What is the role of the large intestine in the digestive system?
Absorbs water from undigested food producing faeces
What is the role of enzyme in the digestive system?
enzymes act as biological catalyst which speed up the rate of biological reactions (the breakdown of food) without being used up
How does the shape of an enzyme affect its function
Enzymes have a specific active site which is complementary to their substrate
What is metabolism
The sum of all the reactions in a cell or an organism
What type of metabolic reactions do enzymes catalyse?
Building larger molecules from smaller molecules (glucose to starch)
Changing on molecule to another (glucose to fructose)
breaking down larger molecules into smaller molecules (carbohydrate to glucose)
What is the lock and key hypothesis of enzyme function
The shape of the enzyme active site and the substrate are complementary, so can bind together to form an enzyme-substrate complex
How does temperature affect enzyme action?
Up to a certain point, increasing temperature increases enzyme action, as molecules have a higher kinetic energy. Above a certain temperature, the shape of the active site is altered and the enzyme becomes denatured, so it can no longer catalyse the reaction. The optimum temperature is around 37 degrees Celsius
How does pH affect enzyme function?
The optimum pH for most enzymes is 7 (apart of protease in the stomach). If the pH is too extreme, the shape of the active site may be altered and the enzyme may no longer work
Where are amylase, protease and lipases produced in the body
Carbohydrases- amylase - salivary gland and pancreas; Maltese- small intestine
proteases: pepsin- stomach; others-pancreas and small intestine
Lipases: pancreas and small intestine
What is the role of amylase in the digestive system
Amylase breaks down starch into maltose and maltase break down maltose into glucose
What is the role of protease in the digestive system?
proteases break down proteins into amino acids,
What is the role of lipases in the digestive system?
lipases break down lipids into fatty acids and glycerol
How are the products of digestion used?
They are used to build bigger molecules.
Glucose is used as a substrate in respiration
Where is bile made and stored in the body
Bile is made by the liver and stored in the gallbladder
What is the role of bile in the digestive system?
Bile is an alkaline substance which neutralises the hydrochloric acid secreted by the stomach
Bile emulsifies lipids to form droplets- this increases the surface area for the lipases enzyme to work on
What is the heart?
An organ that pumps blood around the body
What is the purpose of the circulatory system
carries oxygen and other useful substances to bodily tissues, and removes waste substances
How does the double circulatory system work?
One pathway carries blood from the heart to the lungs- where the gaseous exchange of oxygen and carbon dioxide
one pathway carried the blood from the heart to the tissues
Where does blood pumped by the right ventricle go?
the lungs by the pulmonary artery
Where does the blood pumped from the right ventricle
Body tissues
Why is the double circulatory system important?
it makes the circulatory system more efficient- for example oxygenated blood can be pumped around the body at a higher pressure by the left ventricle
How many chambers does the heart have and what are they called
4-right atrium, right ventricle , left atrium, left ventricle
Why is the wall of the left ventricle thicker?
The left ventricle has to pump blood at a higher pressure around the whole body
What are the four main blood vessels associated with the heart?
Aorta (left): carries oxygenated blood from the heart to the body
Pulmonary vein (left): carries oxygenated blood from the lungs to the heart
Vena cava (right): carries deoxygenated blood from the body to the heart
Pulmonary artery (right)- carries deoxygenated blood from the hear to the lungs
What is the purpose of valves in the heart?
prevent the back flow of blood
What is the purpose of coronary arteries?
Coronary arteries supply the heart muscle with oxygenated blood
Describe the process of blood flow through the heart
Blood enters the right atrium via the vena cava and the left atrium via the pulmonary vein
The atria contract , forcing blood into the ventricles and causing valves to shut
After the ventricles contract, blood in the right ventricle enters the pulmonary artery (to the lungs) and blood in the left ventricle enters the aorta (to the body)
What is the approximate value of the natural resting heart rate?
70 beats per minute
How is the heart rate controlled?
Heart rate is controlled by a group of cells in the right atrium which act as a pacemaker. They release waves of electrical activity which cause the heart muscle to contract
How can an abnormal heart rhythm be treated?
using an artificial pacemaker which sends out electrical signals to correct the heart’s rythm
What are the three types of blood vessel in the body?
Arteries
Veins
Capillaries
How are arteries adapted for their function
Function: carry blood away from the heart
Thick muscle layer- adds strength to resist high pressure
Thick elastic layer- allows arteries to stretch and recoil - in order to withstand high pressure
How are veins adapted for their function?
function: carry blood towards the heart
wide lumen- enables low pressure
valves- prevent back flow of blood
How are capillaries adapted for their function
function: enable transfer of substances between the blood and tissues
walls are one cell thick- short diffusion path
permeable walls - substances can diffuse across
narrow lumen- blood moves slowly-more time for diffusion
How would you calculate the rate of blood flow?
volume of blood/number of minutes
Where are the lungs found in the body?
The lungs are located in the thorax (within the chest)
They are protected by the ribcage and separated from the rest of the abdomen by the diaphragm
What tissues and organs make up the gas exchange system?
Trachea
Intercostal muscles
Bronchi
Bronchioles
Alveoli
Diaphragm
Explain how the lungs are ventilated by the action of intercostal muscles
Intercostal muscles contract
Ribcage moves upwards and outwards
Diaphragm flattens and volume of the chest increases
Increased volume results in decreased pressure
Air is drawn into lungs down pressure gradient
The inverse occurs when air moves out of the lungs
Describe how gas exchange occurs at the alveoli
Oxygen diffuses from the alveoli into the capillary bloodstream down its concentration gradient
Carbon dioxide diffuses from the capillary the alveoli down its concentration gradient
Describe how alveoli are adapted for gas exchange
small and arranged in clusters- larger surface area
rich blood supply- maintains concentration gradient
thin alveolar wall- short diffusion pathway
How would you calculate the breathing rate
number of breaths/number of minutes
What substance carries the different components of blood around the body?
plasma
what substance are transported by plasma?
red blood cells
white blood cells
platelets
carbon dioxide
urea
products of digestion
What is plasma?
a yellow liquid within blood that transports substances around the body
What is the purpose of red blood cells in the blood
transport oxygen around the body
How are red blood cells adapted for their function
biconcave shape- increased surface area to volume ratio
no nucleus- more room for haemoglobin to bind to oxygen
contains haemoglobin- binds to oxygen
What is the purpose of white blood cells in blood?
they form part of the immune system, protect the body from invading pathogens
How are white blood cells adapted for they function?
have a nucleus- contains DNA which codes for proteins
can produce antibodies
can produce antitoxins
can engulf and digest pathogens (phagocytosis)
What is the purpose of platelets in blood?
Platelets are small cell fragments which aid the clotting of blood at the site of a wound
Why is the function of platelets important?
Platelets aid in the process of blood clotting (conversion of fibrinogen to fibrin). As a result, red blood cells are trapped in the fibrin network, forming a clot which prevents excessive bleeding.
Scab formation prevents bacteria entering the wound
What is coronary heart disease?
coronary heart disease occurs when the coronary arteries that supply the heart muscle become blocked with a buildup of fatty material. This restricts the supply of oxygen to the heart, possibly leading to a heart attack or death
What is a stent and how does it work?
A stent is a metal mesh tube that is inserted into a blocked artery so that it remains open. The stent is inflated using a balloon, which is later removed to allow blood to flow freely
What are the advantages and disadvantages of stents?
Advantages
- insertion can be carried out without general anaesthetic
-quick recovery time
-lower the risk of heart attack
Disadvantages
-Risk of postoperative infection
-Risk of blood clots at site of stent
What are statins?
statins are drugs which reduce the level of LDL (bad) cholesterol which contributes to the development of coronary heart disease
What are the advantages and disadvantages of statins?
Advantages
-Reduce risk of strokes, coronary heart disease and heart attacks
-Increase level of HDL (good) cholesterol
Disadvantages
-have to be taken continuously
-may have side effects
-effect may not be immediate
What is a heart bypass surgery?
A surgery where blocked coronary arteries are replaced with sections of veins taken from other parts of the body
What are the consequences of leaky heart valves?
Blood flows in the wrong direction, causing the heart to be less efficient
patients may become breathless and die as a reslut
What types of valves can replace leaky valves?
-Mechanical- made of metal or polymers
Biological- taken from animals (pigs, sometimes humans)
What are the advantages and disadvantages of mechanical valves
Advantages
-last for a very long time
Disadvantages
-Need to take medication to prevent blood clotting around valve
What are the advantages and disadvantages of biological valves?
Advantages
-work very well- no medication required
Disadvantages
-only last 12-15 years
What is the purpose of an artificial heart
Artificial hearts are intended to support a patient’s heart while they wait for a suitable donor heart
What are the advantages and disadvantages of artificial heart
Advantages:
-less likely to be rejected by immune system
-allows damaged heart to rest to help recovery
Disadvantages
-Risk of infection
-Risk of blood clots
- Have to take blood-thinning drugs
What is health?
Health is the state of physical and mental wellbeing
What is communicable disease?
A disease caused by a pathogen which can be transmitted from one person to another
What is non-communicable disease?
A disease which can not be transmitted from a person
How can diet affect health
Too little food/lack of nutrition
Too much food/ too much unhealthy food
How can stress affect health
Prolonged stress is linked to a wide range of health problems including heart disease, cancers and mental health issues
How can life situations affect health?
many life factors such as location, gender, financial status, ethnic group and healthcare provision can impact a persons mental and physical health
Give examples of how health problems can interact
infection with certain viruses can lead to cancer
A compromised immune system can lead to a higher risk of infection with communicable diseases
immune reactions caused by a pathogen can trigger allergic reactions
problems with physical health can lead to mental health issues
What is a risk factor?
A risk factor is an aspect of a person’s lifestyle or a substance found in the body or the environment which can increase the risk of a disease
What is a casual mechanism?
A mechanism which demonstrate how one factor biologically influences another
How do diet, smoking and exercise affect the development of cardiovascular disease?
Diet: high levels of LDL cholesterol causes arteries to become blocked, increasing blood pressure and risk of heart attack
Smoking: nicotine increases heart rate; other chemicals damage the artery lining and increase blood pressure
Exercise: lowers blood pressure, reducing strain on the heart
How does obesity affect the development of type 2 diabetes
obesity is strongly linked with the onset of type 2 diabetes- a disease in which the body stops responding to insulin
How does alcohol affect liver and brain function?
excessive long-term alcohol use may lead to liver cirrhosis (scarring of the liver)
increases risk of liver cancer
damages brain tissue and nerve cells
How does smoking affect the development of lung disease and lung cancer?
tar in tobacco can damage the alveoli of the lungs, leading to chronic obstructive pulmonary disease (COPD)
Tar also damages the cells which line the lungs, leading to lung cancer
How do smoking and alcohol affect unborn babies?
carbon monoxide from tobacco smoke reduces the amount of oxygen the foetus receives, which can lead to premature birth or stillbirth
Alcohol passes across the placenta and damages the developing foetus. Once born, the baby may have a number of deformities and health problems as part of foetal alcohol syndrome
How do carcinogens affect the development of cancer?
ionising radiation is a type of carcinogen which can cause mutations in DNA, potentially leading to cancer
What is cancer?
Cancer is the development of a tumour as a result of uncontrolled cel division
What is a benign tumour?
A tumour that is contained in one location usually within a membrane
They are not cancerous and don’t invade other parts of the body
can grow large very quickly- may cause damage to another organ
What is a malignant tumour?
A tumour that can spread around the body via the blood and lymphatic system
Can invade other tissues (metastasis)
Cells divide more rapidly and have a longer lifespan
Disrupts healthy tissues and may lead to death
Give examples of factors which can lead to cancer
Genetics- certain genes increase the risk of breast and ovarian cancer
Smoking
Obesity
Ionising radiation- UV lights and X-rays
Viral infections
