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Topic 2 Organisation By Bethan Poole (2.2 Animal Tissues, Organs and organ…
Topic 2 Organisation
By Bethan Poole
2.1 Princples of Organisation
Cells= building blocks of
ALL
living things Not solid structures
Tissue
- Goup of cells doing the same thing
#
Organs
- Group of tissues that work together to perform a funtion e.g. Heart
#
Organ system
- Group of organs performing a specific function
2.2 Animal Tissues, Organs and organ Systems
2.2.4 Coronary heart disease
Layers of fatty material build up inside the conorary arteries and narrow them
Reduces flow of blood through them- can lead to angina or a heart attack
Treatments
Stents
Keep the conorary arteries open
Statins
Reduce blood cholesterol levels and slow down the rate at which fatty materials build up
Faulty Valves
Can be replaced using biological or mechanical valces
Heart failure
Donor heart, or heart and lungs can be transplanted
Artificials hearts used for patients while waiting for a transplant
Drugs
Advantages
Reduces chances of a heart attack/stroke, can be used to treat high cholesterol that runs in the family
Disadvantages
Rely on drugs
Still eat the same things
Still overweight, can cause liver damage
Mechanical devices
Advantages
Can improve long term quality of life
Disadvantages
Damage red blood cells
Require anti-cloating drugs
2.2.5 Health issues
Health
- State of physical and mental well-being
Disease
- caused by part of the body not working properly- can affect physical and mental health
Communicable diseases
can be spread between organs
Non-communicable diseases
cannot be spread
Diseases can interact
e.g.
Viruses infecting cells can be triggered for cancers, such as cervical cancer
If a person is physically ill it can lead to depression and mental illness
Immune reactions triggered by a pathogen can cause allergies, such as skin rashes and asthma
Diseases such as HIV and diabetes can change a persons life and cost countries large sums
Roughly 10% of the health budget in Britain is spent on people with diabetes
2.2.3 Blood
It is a tissue
Made of
plasma
which contains three things
Red blood cells
Contain
haemoglobin
, binds to oxygen to transport it from the lungs to the tissues and cells, which need it for respiration
Don't have a nucleus - more room for haemoglobin
Very small- can fit through tiny capillaries
Shaped like bioconcave discs, large surface area that oxygen can quickly diffuse across
White blood cells
Help protect the body against infection
Can change shape, so they can squeeze out of the blood vessels into the tissues or surround it and engulf microorganisms
Platelets
Fragments of cells, collect at wound and trigger blood clotting
Plasma transports various chemical substances around the body- i.e. products of digestion, hormones, antibodies, urea and Carbon dioxide
2.2.6 The effect of lifestyle on some non-communicable diseases
Impacts of lifestyle choices
Financial
Health
Social
Individual
Local
National
Global
Risk Factors
Can be:
Substance in a persons body
aspect of someones lifestyle
Sometimes there are clear links between a risk factor and the chance of getting a disease
This doesn't mean the risk factor causes the disease
Scientists have to look for a
causal mechanism
to prove that a risk factor is involved
E.g
Cariovascular disease
Lack of exercise/smoking/high intake of saturated fat
Type 2 diabetes
Obesity
2.2.2 The heart and blood vessels
Blood vessels
The blood passes around the body in blood vessels
Three different types
Veins
Take blood from your organs to your heart
Thinner walls and valves prevent back flow
Arteries
Take blood from heart to your organs
Thick walls made from muscle and elastic fibres
Capillaries
Allow substances produced by the cells to pass in and out of the blood
Narrow thin-walled blood vessel
Heart
Pumps blood around the body in a
double circulatory system
Blood passes through the heart twice on each circuit
Chambers of the heart
Left and right
atria
-recieve blood from veins
Left and right
ventricles
-pump blood to the arteries
(1)
Blood enters the heart through the atria- Vena cava or pulmonary vein
(2)
The atria contracts and force blood into the ventricles
(3)
Ventricles then contract and force blood out of the heart- Aorta or Pulmonary Artery
Valves make sure blood flows in the correct direction
Gaseous Exchange
Heart sends blood to the lungs via the
pulmonary artery
Air obtained by breathing reaches the lungs via trachea
The trachea divides into two tubes- the
bronchi
and they divide to form
bronchioles
which divide until they end in tiny air sacs
alveoli
Alveoli are adapted:
Large surface area
Moist
Rich blood supply
Thin(one cell thick)
2.2.7 Cancer
Non-communicable disease
Caused by normal cell mutating and turning into cancerous cells (Change in genetic code)- Rate of division increases
Two types of tumours
Benign
Do not spread around the body
Maligant
Spread
Travel in the blood and form secondary tumours in other parts of the body
There are some genetic risk factors for some cancers- may run in the family
Lifestyle risk factors
Smoking
Obesity
Common viruses
UV exposure
2.2.1 The human digestive system
Digestion by enzymes
Breaking large insoluble molecules down into small, soluble molecules so they can be absorbed through the wall of the small intestines
(1) Mouth
Mechanical digestion
Teeth churn food into smaller molecules, increasing surface area
Chemical digestion
Amalayse- made in the salivary gland digests starch into glucose
(2) Oesophagus
Peristalsis- Muscles contract above the bolus (mixture of food and saliva) to push food down through the oesophagus
(3) Stomach
Part 1
Hydrochloric acid- pH2- kills bacteria , creates the right conditions for enzymes to work
Mucus stomach lining- Protects wall of stomach from HCl- gap causes ulcers
Part 2
Mechanical digestion
Muscluar wall churn th food
Chemical digestion
Enzymes digest large insoluble molecules
(4) Small intestines
Part 1
Bile (alkali)
Emulsifies fat, increasing surface area enabling lipase to digest fats more easily
Produced in liver, concentrated in gall bladder
Neutrilises stomach acid
Creates correct conditions for enzymes
Part 2
All digestible molecules are now soluble and absorbed through the walls of the small intestine into the blood by diffusion- Villi increase surface area of the small intestines
Undigested food moves to large intestine by peristalsis-
Note
- vitamins and minerals are already small and soluble so do not need to be digested to be absorbed
(5) Large Intestines
Any remaining water is absorbed into the blood stream
Waste is removed to the rectum then anus
Catalysts
Protease
e.g. Pepsin, Trypsin
Breaks Protein into amino acids
Made in Small intestines, Pancreas, Stomach
Carbodyrase
e.g Amalayse
Breaks starch into glucose
Made in Small Intestines, Pancreas, Salivary Gland
Lipase
Breaks Fat into fatty acids
Made in small intestines and pancreas
Optimum pH for each enzyme
Amalayse
Converts starch into sugar- pH 7
Pepsin
Breaks down proteins into peptides- pH8
Trypsin
Breaks dow peptides into amino acids- pH 8
Lipase
Breaks down lipids into fatty acids and glycerol- pH9
Sucrase
Breaks down sucrose into glucose and fructose- pH9
Lactase
Breaks down lactase into glucose- pH 9
Lock and Key
Reactant fits into the enzyme like a lock and key - have to be the right shape to work
Temperature and pH change
When enzymes are heated above 40°C, the shape of the active site changes. This is called denaturing and is irreversible
2.3 Plant Tissues, Organs and Systems
2.3.1 Plant tissues
Epidermis
- Covers outer surfaces of the plant for protection
Palisade Mesophyll
- Main site of photoshynthesis
Spongy mesophyll
- Air spaces between the cells , allows gases to diffuse through the leaf
Xylem Vessels
- Transport water and minerals from root to leaves, supports the plant
Phloem Vessels
- Transports dessolved food materials through the plant
Meristem Tissue
- Found mainly at tips of the roots and shoots, where it can produce new cells for growth
2.3.2 Plant organ systems
Root hair cell
Large surface area
For uptake of water by osmosis and mineral ions by active transport
Xylem
Transport water and mineral ions from root to stem and leaves-
Transpiration
Phloem
Transport dissolved sugars from the leaves to the rest of the plant for immediate use or storage-
Translocation
Transpiration
Factors affecting it
Temperature
Humidity
Air movement
Light intensity
Transpiration
Movement of water through the plant from root to leaf- Occurs in Xylem
Translocation
Movement of sugar from the leaves to the other parts of the plant- Occurs in phloem
Active transport
Movement of substances against the concentration gradient- requires a lot of energy
Somata And Guard cells
Role of guard cell is to open and close the stomata
At night stomata is closed- carbon dioxide is not needed for photosynthesis
When water is plentiful, guard cells take up all the water and bend causing the stomata to open
When water is scarce, losing water makes the stomata change shape and close
Role is to control gas exchange and water loss