Transport in animals

Why do multicellular animals need transport systems?

Why do multicellular animals need transport systems?

Size, metabolic rate and surface area to volume ratio

Open circulatory system

Blood flows freely in the body cavity and surrounds the organs.

Closed circulatory system

Blood is kept inside vessels, moving faster and more efficiently.

Single closed system

Blood passes through the heart one which is less efficient.

Double closed system

Blood passes through the heart twice for faster circulation.

Veins

Carry deoxygenated blood (except the pulmonary vein) towards the heart

Vein structure

Veins have walls containing less elastic fibre, less smooth muscle and valves

Arteries structure

Arteries have walls containing lots of elastic fibres and smooth muscle.

Capillaries

Are microscopic blood vessels that link the arterioles and venules.

Capillary structure

Capillaries have a small lumen, walls are one cell thick and there are fenestrations in the endothelium.

Cell

Makes up all living organisms and contains organelles.

Tissue

A group of cells working together to perform a shared function.

Organ

A structure made up of groups of different tissues working together to perform specific functions.

Organ system

A group of organs with related functions, working together to perform functions within the body.

Stem cells

Undifferentiated cells that are not adapted to a particular function and have the potential to differentiate to become a specialised cell.

Sources of animal stem cells

Embryonic stem cell and adult tissue stem cells (bone marrow)

Differentiation of erythrocytes (4)

Cells become smaller, are enucleated, they have a biconcave shape and are flexible

Differentiation of neutrophils (2)

Their nucleus is multi-lobed and contain granular cytoplasm containing lysosomes.

Tissue fluid composition

Water, oxygen, glucose, amino acids, small proteins and white blood cells.

Hydrostatic pressure

The blood is under high hydrostatic pressure from the heart contracting, forcing fluid out of the capillaries forming tissue fluid.

Oncotic pressure

Blood exerts osmotic pressure due to plasma proteins giving the blood a high solute potential.

Blood plasma composition

Water, oxygen, glucose, amino acids, large proteins, red blood cells, white blood cells and platelets.

Lymph production

The remaining tissue fluid is drained into lymph capillaries which return to the blood.

Lymph composition

Proteins, lipids and white blood cells.

Amino acid structure

Amine group, carboxyl group and R-group.

R-group

A range of chemical groups different in each amino acid

Amine group

NH2

Carboxyl group

COOH

Synthesis of peptides

Amino acids join when the amine (H) and carboxyl groups (OH) react in a condensation reaction to form a dipeptide.

Synthesis of proteins

Different R-groups interact forming hydrogen and ionic bonds and disulphide bridges.

Hydrogen bonds

Weak bonds between amine and carboxyl groups.

Ionic bonds

Strong bonds between oppositely charged R-groups

Disulphide bonds

Covalent bonds between R-groups containing sulphur atoms.

Primary protein structure

The sequence in which amino acids are joined by peptide bonds - directed by DNA

Secondary protein structure

The oxygen, hydrogen and nitrogen atoms interact forming 3D structures including an alpha helix and beta-pleated sheet.

Tertiary protein structure

The folding of a protein into its final shape as R-groups interact.

Quaternary structure

The association of 2 or more proteins called sub-units.

Globular protein structure

Compact, spherical and soluble

Conjugated protein structure

Globular proteins containing a non-protein (prosthetic) group.

Fibrous protein structure

Form longs strands and are insoluble in water.

Collagen

A fibrous protein made up of a triple helix of polypeptide chains used as a structural component in skin, bones and walls of blood vessels.

Haemoglobin structure

A conjugated protein made up of 4 polypeptide chains containing an iron-containing haem group.

Keratin

A group of fibrous proteins found in the hair and nails containing cysteine which allows disulphide bridges to form.

Elastin

A fibrous protein found in elastic connective tissue such as the walls of blood vessels.

Insulin structure

A globular protein known as a hormone used to regulate blood glucose concentration.

Amylase

A globular protein known as an enzyme responsible for the breakdown of starch into maltose made up of a single polypeptide chain.

Role of haemoglobin

Oxygen binds to iron in haem groups forming oxyhaemoglobin which can be transported via blood to respiring body tissues.

high partial pressure of oxygen

Haemoglobin has a high affinity for oxygen and binds with it so saturation is nearly 100%.

low partial pressure of oxygen

Haemoglobin has a low affinity for oxygen and releases it so saturation is low.

Cooperative nature of oxygen binding

When haemoglobin binds with one oxygen, it changes shape so it becomes easier to bind another oxygen.

Feral haemoglobin

Has a higher oxygen affinity than the mothers, allowing the oxygen to dissociate from the mother’s haemoglobin and bind with the fetal haemoglobin.

Bohr effect

At higher partial pressures of CO2 haemoglobin has a lower affinity for oxygen and releases it to respiring tissue.

Carbon dioxide to ions in red blood cells

CO2 reacts with water to form carbonic acid by the enzyme carbonic anhydrase. Carbonic acid dissociates to hydrogen and hydrogen carbonate ions.

Ions to CO2

Hydrogen ions bind with haemoglobin to form haemoglobinic acid causing oxygen to be released. When blood reaches the lungs, the low partial pressure of CO2 causes ions to reform CO2.

Chloride shift

Hydrogen carbonate ions leave red blood cells while chloride ions enter to maintain the charge balance.