B4: Organising animals and plants

What does plasma do?

transports all of your blood cells (+other substances) around body

What does plasma transport?

C02 - produced by cells and carried to lungs

urea - formed in liver = break down of excess proteins - moved to kidneys --> removed from blood --> urine

small soluble products of digestion --> small intestine --> plasma --> individual cells

Function of red blood cells?

carries oxygen form lungs and carries to cells where it's needed

Adaptations of red blood cells + how it works - discs

biconcave discs - increased surface area to volume ratio - diffusion

Adaptations of red blood cells + how it works - ha

have haemoglobin - red pigment that binds to oxygen

Adaptations of red blood cells + how it works - nuc

no nucleus - more space for haemoglobin

What is the route of the red blood cells

alveolus of lungs --> red blood cell --> body organ -->

Describe a white blood cell

have a nucleus, form parts of the body's defence system

Function: lymphocytes

form antibodies against microorganisms

Function of white blood cells

form antitoxins against poisons

Function: phagocytes

Engulf and digest invading bacteria + viruses

Describe platelets - what they are + structure

small frangments of cells, have no nucleus

Function: platelets

helps blood to clot at site of wound

What is blood clotting

a series of enzyme controlled reactions - converting fibrinogen to fibrin, produces network of protein fibres which captures lots of red blood cells + platelets (dries to form scab)

Function: scab

protects new skin as it grows and stops bacteria entering body (through wound)

percentage of plasma in blood

55%

percentage of cells + platelets in blood

percentage of red blood cells in blood

45%

Where is oxygen transported from + to and why?

lungs --> respiring cells Purpose: aerobic respiration

Where is C02 transported from + to and why?

Respiring cells --> lungs Purpose: waste - excreted

Where is urea transported from + to and why?

Liver --> Kidney, purpose: excess amino acids excreted

Where is amino acids transported from + to and why?

Small I. --> Cells - purpose: makes protein, small i. --> liver - purpose: broken down --> urea

Where is soluble products of digestion transported from + to and why?

Small I. --> cells - purpose: respiration + growth

Function: capillaries

where exchange of substances between the blood and tissue occurs

Function: arteries

oxygenated blood - heart --> organs (away from heart)

Function: vein

deoxygenated blood - organs --> heart (into heart)

Lumen size: capillaries

tiny vessel with narrow lumen

Lumen size: arteries

small lumen

Lumen size: veins

large lumen

Wall thickness: capillaries

a single layer thick to allow diffusion

Wall thickness: arteries

thick walls - support during high pressure

Wall thickness: veins

relatively thin walls

Muscle: capillaries

no muscle or elastic tissue

Muscle: arteries

thick layer of muscle and elastic fibres to withstand high blood pressure

Muscle: veins

thinner layers of muscle and elastic because blood is at lower pressure

Extra info: capillaries

Lots of them - provides a huge surface area for the exchange of substances

Extra info: arteries

walls can stretch and recoil to keep up/ support pressure

Extra info: veins

often have valves to prevent backflow of blood

What is double circulation

Circulation of blood from heart to lungs is separate from circulation from heart to the rest of the body

What animals have double circulation

humans and other mammals

Where does the pulmonary circulation carry blood from/to

heart (deoxygenated) --> lungs --> (oxygenated) heart

Where does the systemic circulation carry blood from/to

heart (oxygenated) --> organ --> (deoxygenated) heart

Path of pulmonary circulation

Right of heart --> pulmonary artery --> lungs --> capillaries --> pulmonary veins --> left heart

Path of systemic circulation

Left of heart --> aorta --> body/organs/respiring tissue --> vena cava (vein) --> right of heart

Why is double circulation used?

Blood passes throught the heart twice so that after it's oxygenated, it can be pumped quickly at a high pressure to the tissues to enable a high metabolic rate/activity

Double circulation route

Right atrium --> right ventricle --> pulmonary artery --> lungs --> pulmonary vein --> left atrium --> left ventricle --> aorta --> body --> vena cava --> right atrium

What happens with cardiovascular disease

Fatty material builds up in the lining of coronary artery (which is narry) and reduces blood flow to heart muscle. Heart muscle runs out of oxygen --> pain/possibly cell death/heart attacks

What do stents do

solution to cv disease, allows blood to flow freely, pushes the fats to the side

Advantages of stents

minor surgery, lets blood flow freely, can be placed almost anywhere in the body, only need local anaesthetic - person can be conscious

Negatives of stents

could block up another place, expensive

How does coronary artery bypass surgery do/work?

solution for cv disease, replaces the blocked coronary artery with bits of veins from other parts of the body

Advantages of coronary artery bypass surgery

can be use anywhere

Disadvantages of coronary artery bypass surgery

possibility of infection, risk of a stroke or heart attack during or after the surgery due to complications like blood clots.

How do statins do/work?

A group of drugs which reduce blood cholesterol levels and this slows down rate of fatty deposits

Advantages of statins

Brings down blood cholesterol, no surgery, slows down fatty deposits

Disadvantages of statins

Drugs can have side effects

Describe leaky valves

Heart valves can weaken and leak --> breathless and death if really bad

Function: heart valves

keeps the blood flowing in the right direction

Advantages of mechanical valves

Solution for leaky valves, cheaper than biological, lasts a long time (20-30 yrs)

Disadvantages of mechanical valves

have to take medicine for life - stop blood clots, major surgery

Advantages of biological valves

taken form animals e.g. pigs, lower risk of l=clots, no medication required

What is a natural pacemaker

A group of natural pacemaker cells near right atrium to keep the hart beating at a steady rhythm

What happens if the natural pacemaker stops working

Slower heartbeat --> reduces oxygen transport to muscles, too fast - blood not pumped correctly

Describe artificial pacemakers

An electrical device implanted under the skin and chest which sends electrical signals to stimulate the heart to beat properly - corrects irregularities in heart rate

Advantages of artificial pacemakers

Increases length of life, modern ones - very sensitive to body needs e.g. stimulates heart faster when exercising

Disadvantages of artificial pacemakers

Regular medical check-ups needed throughout your life

What factors affect the rate of diffusion

Short diffusion distance, large concentration gradient, large surface area, temperature (not in the body)

Alveoli Adaptations?

Short diffusion distance - one cell thick (flattened), large concentration gradient - breathing (high oxygen conc.) - flow of blood (deoxygenated), lots of alveoli

Inhalation + exhalation: intercostal muscles

Intercostal muscles contract then relax

Inhalation + exhalation: ribs

Move upwards and out then move downwards and in

Inhalation + exhalation: air

Drawn into the lungs, forced out of the lungs

Inhalation + exhalation: volume

Volume of chest increases, volume of chest decreases

Inhalation + exhalation: pressure

Pressure in chest increases, pressure inside chest decreases

Inhalation + exhalation: Diaphragm

Diaphragm contracts and flattens, diaphragm relaxes and moves upwards

Adaptations of leaves - large

Large surface area - more sunlight hitting leaf + more absorbed

Adaptations of leaves - thin

Shorter diffusion distance

Adaptations of leaves - small holes

Small holes allow gas exchange - stomata, allows CO2 in and O2 out, can lead to water loss

Adaptations of leaves - chloroplasts

Chloroplasts packed with chlorophyll - photosynthesis can take place

What is a cuticle + function?

A layer of wax that waterproofs the leaf - reducing water loss

What is a upper epidermis + function?

Thin, transparent layer that ensures that maximum amount of light reaches the photosynthesising cells

What is a palisade mesophyll + function?

The main photosynthetic layer of leaf - at top where there's most light - lots of chloroplasts to maximise light absorption

What is a spongy mesophyll + function?

Layer of loosely packed cells with many air spaces - allows easier diffusion of gases and increases the surface area

What is a xylem + function?

Hollow tubes strengthened by lignin - transports water and minerals up stem from roots to leaves

What is a phloem + function?

Tubes of living cells - very little contents which transport sugars from leaf to non-photosynthesising cells for immediate use of storage

What is a guard cells + function?

Specialised cells - able to open the stomata to allow gas exchange and close them to reduce water loss

What is a stomata + function?

Pores in leaf which allow CO2 to diffuse into the photosynthesising cells

Definition of a statin

Drugs used to lower blood cholesterol levels and improve the balance of HDLs and LDLs in the blood

Definition of pulmonary vein

Large blood vessel that carries oxygenated blood away from the lungs back to the left atrium of heart

Definition of the pulmonary artery

Large blood vessel that takes deoxygenated blood from the right ventricle of the heart to the lungs

Definition of aorta

Artery that leaves the heart from the left ventricle and carries oxygenated blood to the body

Definition of a pacemaker

A group of cells found in the right atrium of the heart that controls the basic rhythm of the heart beat

Definition of conducting fibres

Fibres which carry the electrical impuls from the pacemaker cells to the heart tissue

Definition of ventricle

Chambers of the heart that contract to force blood out of the heart

Definition of atria/atrium

Upper chambers of the heart

Definition of a heart valve

Tissue that separates 2 areas of the heart and ensure that blood flows in the right direction

Definition of the vena cava

Large vein that brings deoxygenated blood from the body to the ears

Definition of a stent

Metal mesh that is used to open up a blocked blood vessel

Definition of a coronary artery

The blood vessels that supply oxygenated blood to the heart muscle

Path of air during inhalation + exhalation

nose, trachea, bronchi, bronchioles, alveoli, O2 diffuses into capillaries, CO2 diffuses out of capillaries, alveoli (back the same way)