B4: Organising Animals and Plants

Topics covered: White/Black - Blood and the Heart Yellow - Coronary Heart Disease Blue - Gas Exchange in the Lungs Red - Plant Tissues/Structure Purple - Transpiration Green - Plant Adaptations to reduce water loss

Arguments for use of blood products

Can save peoples lives.

Only option to treat anaemic patients, people in chemotherapy or people post-surgery

Arguments against use of blood products

Needles could be contaminated

Blood could be rejected, even if it the same type

Religious objection (Jehovah’s Witness)

Plasma

A yellow liquid which carries red and white blood cells

Platelets

A small fragment of cell which has an important job in blood clotting

White Blood Cells (Lymphocytes)

Fight disease. Have a nucelus, and release antibodies and antitoxins

Red Blood Cells

Carry oxygen. Have haemoglobin which sticks to oxygen, have a bi-concave shape, can change shape and have no nucleus for more shape to carry oxygen.

Why do mamals have a double circulatory system?

Blood from the body is deoxygenated. It has to be pumped to the lungs at low pressure to be oxygenated. Then it returns to the heart to be pumped around the body at high pressure.

Arteries

Carry blood away from the heart. Have thick muscular and elastic walls. Usually carry oxygenated blood (except for the pulmonary artery). Pump high pressure blood so have thick elastic walls to prevent tearing.

Veins

Thin-walled wide vessels, which carry blood towards the heart. Slow lowing blood. They use the skeletal muscle contraction to ensure blood flows in only 1 direction. Have valves to prevent blood from going the wrong way.

Capillary

Very small. Exchange substances with cells (nutrients + oxygen). Take away waste products. Walls are only one cell thick and permeable. Small lumens, but there are a lot of capillaries. Blood has low pressure (flows slowly). Only 1 blood cell fits through the lumen.

Which side of the heart carries de/oxygenated blood?

Right side is oxygen poor

Left side is oxygen rich

Flow of blood through the heart

Deoxygenated blood enters the right atrium via the vena cava. The right atrium contracts and the blood is forced into the right ventricle, through the atrioventricular vales. The right ventricle contracts and the blood is pumped into the pulmonary valves. The blood is transported to the lungs where the carbon dioxide diffuses out into the lungs and oxygen diffused into red blood cells, binding to haemoglobin. The blood (now oxygenated) returns tot the heart at a lower pressure via the pulmonary vein and enters the left atrium. The left atrium contracts and the blood is forced into the left ventricle through the atrioventricular valves. The left ventricle contracts and the blood is forced under high pressure into the aorta. It is then transported around the rest of the body.

Why is the Cardiac muscle thicker on the left side of the heart?

Because it has to pump blood around the whole body.

Sinoatrial node

The heart has a natural pacemaker, which regulates heart rate. It is called the sinoatrial node and is a group of cells located in the upper wall of the right atrium.

Treatment for Arrythmia

If a person has irregular heart beat, they can have a natural pacemaker fitted. It is inserted into the skin on the chest under the collarbone, and sends electric impulses to the sino-atrial node.

Word equation for aerobic respiration

Glucose + Oxygen —> Carbon Dioxide + Water + Energy

Word equation for anaerobic respiration in animal cells

Glucose —> Lactic Acid

The coronary blood vessels supply blood to the heart muscle.

Balanced chemical equation for respiration

6O2 + C6H12O6 —> 6CO2 + 6H2O

Coronary Heart Disease

In coronary heart disease layers of fatty material build up inside the blood vessels which narrows the. This reduces the blood flow to the heart muscle. This in turn means that the heart muscle receives less oxygen and glucose for respiration. So less energy is released for contraction of the heart muscle.

Risk Factors for Coronary Heart Disease

Increasing age, smoking, inactivity, alcohol drinking, type 2 diabetes, high stress, obesity, high blood cholesterol and pressure.

Statins

Statins are tablets that are taken once a day that lower the level of LDL cholesterol in the blood, usually taken just before bed. In most cases, treatments with statins continues for life, as stopping the medication causes your cholesterol to return to a high level within a few weeks. It can also interact with other medicines, increasing the risk of unpleasant side effects like muscle damage.

Heart Valve Replacement

A valve replacement involves removing a faulty or damaged valve and replacing it with a new one made from synthetic materials or animal tissue. It is not suitable for everyone and can take a long time to recover from. There are no medicines to treat aortic valve problems, so this is recommended if there is a risk of serious complication. A large cut is made in the chest, your heart is stopped and a machine is used to take over your heart. The damaged valve is removed and replaces, and your heart is restarted.

Biological heart transplant

A cut is made in the middle of the chest. Your own heart is removed, and the donor heart is connected to the main arteries and veins. The new heart should then begin beating normally. A machine will be used to keep your blood circulation with oxygen-rich blood. You’ll usually need to stay in hospital for around 2/3 weeks after. You will need regular check-ups and take immunosuppressants for the rest of your life. Without them, your body may attack the new heart. There is also a risk of rejection, and immunosuppressants give increases vulnerability to disease.

Statins

Used to widen blocked or narrowed coronary arteries. A thin flexible tube (catheter) is inserted through the groin, wrist, or arm. When the tube is in place, a thin wire is guided down the length of the affected coronary artery, delivering a balloon. The balloon is then inflated to widen the artery, squashing fat against the wall so blood can flow through freely when the balloon is removed.

Breathing

The process of taking air in and out of the lungs (ventilation)

Respiration

The exothermic chemical reaction that happens in cells to release energy.

Intercostal Muscle

Muscles between the ribs. Contract and relax to get air out of the lungs.

Ribs

Made up of bones, protecting the delicate organs underneath and helping us breathe in and out

Alveoli

Where gas exchange happens in the lungs. They are tiny air sacs at the ends of bronchioles.

Bronchioles

The bronchi branch into smaller branches leading to the alveoli

Diaphragm

Muscle under the ribs which contracts and relaxed to get air in and out of the lungs.

Bronchi

Two of these tubes that branch off the trachea. Singular is bronchus.

Trachea

Main airway that passes into the lungs. Branches into 2 branches.

Inhalation

The muscles between the ribs and diaphragm contract. The rib cage moves up and out and the diaphragm flattens. The volume in the chest cavity increases. The pressure in the chest cavity decreases. Air is drawn in from higher pressure in the surrounding air to lower pressure in the luns.

Exhalation

The muscles between the ribs and diaphragm relax. The rib cage moves down and in and the diaphragm becomes dome-shaped. The volume in the chest cavity decreases. The pressure in the chest cavity increases. Air is drawn in from lower pressure in the surrounding air to higher pressure in the lungs.

Alveoli in lungs

Large Surface Area - Spherical shape and many alveoli

Steep Concentration Gradient - Networks of lots of capillaries, ventilation of lungs keeps air flow

Short diffusion pathway - Only two cells thick, lined with a thin film of moisture so gases dissolve

Capillary in leg muscle

Large Surface Area - Huge network of tiny vessels going to huge muscle networks.

Steep Concentration Gradient - Constant blood flow bringing and removing gases

Short diffusion pathway - Walls are a single cell thick

Plant Leaf

Large Surface Area - Broad, large surface area for light to fall on

Steep Concentration Gradient - Lots of veins bring a lot of water, carbon dioxide quickly used in photosynthesis

Short diffusion pathway - Thin, diffusion distance is short

Fish Gills

Large Surface Area - Many gill filaments and gill lamellae

Steep Concentration Gradient - Blood supply in each filament, blood flows in opposite direction to water

Short diffusion pathway - Gill membrane is only one cell thick

Blood leaving the right side of the heart goes where?

The lungs

Waxy Cuticle

Clear, waterproof layer that stops water evaporating out of the leaf

Upper/Lower Epidermis

Outer layer serving as the ‘skin’ covering the plant. Don’t have chloroplasts as their shape makes them inefficient at capturing light. They are important in structure.

Palisade Mesophyll

Long and thin cells which have many chloroplasts to capture more light energy for photosynthesis

Spongy Mesophyll Layer

Spongy section which allows air space for carbon dioxide to diffuse

Vascular Bundle

Made up of separate cells that contain hollow tubes, transporting substances around the cell. This process is called translocation and transpiration

Guard Cells

The cells can open up to allow gases to come in out and out, but also can close to keep water in.

Meristems

Make up the growing tips and shoots that differentiate into all other cell types

Xylem Tissue

Involved in transpiration, and transports water and minerals. Have a hollow structure with thick cellulose walls strengthened by lignin. The cells die to create hollow tubes, and it has non-permeable sides. Moves substances from the roots to the shoots, upwards only.

Phloem Tissue

Involved in translocation, and it moves sucrose (NOT sugar) and amino acids. Sieve tube cells are elongated cells found in phloem tissue. End walls have a lot of holes to allow cell ap to move. Made of living cells, and have companion cells to provide energy. Move substances all around the plant (leaves to roots and shoots) up nd down in both directions.

Transpiration is…

the loss of water from a plant. It is driven by the evaporation of water from the stomata. The path of water through the plant is called the transpiration stream. This involves the movement of water and dissolved mineral ions from the roots, through the xylem vessels and to the leaves.

Factors affecting the rate of Transpiration

Light Intensity (increases with transpiration as the stomata open more for gas exchange)

Air movement (increases with transpiration as winds blows water away outside of the leaf, making a concentration gradient)

Temperature (increases with transpiration as molecules will have more kinetic energy)

Humidity (increases as transpiration decreases as water volume outside of the leaf increases)

Unit of transpiration measured by a potometer

mm³g^-1hr^-1

Summary of water movement throughout the plant

Water moves in from the soil by osmosis. By absorbing minerals the root hair cells help increase concentration gradient. As cells absorb water from the soil, it moves through to the adjacent cell by osmosis. It flows through these pathways to get to the xylem vessels. Water molecules show cohesion and so molecules are dragged up through xylem vessels in the cell. If water doesn’t leave the leaf, no more can be moved through the xylem. The plant needs to balance water loss from the leaf so that it can get more from the roots but not lose too much to wilt. If stomata on the leaf are open, water is lost.

Xerophyte

Plant that has adapted to live in a place with low water conditions

Rolled leaves & Sunken stomata

Traps moist air near the stomata. Reduces water concentration gradient between the leaf and the air, so water loss reduces. Reduces air movement around stomata.

Spikes instead of leaves

Smaller surface area means less opportunity for water to evaporate (e.g Pine Trees)

Hairs on leaves

Traps moist air near the leaf surface. Reduces water concentration gradient. (e.g Pineapple)

Shallow, widespread roots

Widespread or very deep root systems can collect water from a large area or from very deep underground.

Fewer stomata

Reduced number of stomata to reduce water loss by transpiration.

Thick waxy cuticle

Cuticle doesn’t allow water to exit the leaf. Thicker cuticle means less water will escape (e.g Holly Bushes)