Animal Transport (WIP)

Eduqas biology

Why dont single-celled organisms need a transport system?

-SA:V is high

-short distrances to travel

-low metabolic needsWhat

What is insect circulatory system?

open, with a dorsal, tube shaped heart and a fluid filled cavity

How does circulation in insects happen

Blood is pumped at low pressure into the haemocoel where is bathes tghe tissue directly for exchange of materials

Blood slowly returns to the heart and then is pushed forward tp the head where open circulation starts again

circulation system in earthworms

organs are not in direct contact with the blood but are bathed by tissue fluid. Respiratory gases are transported in the blood, aided by a pigment. has dorsal and ventral vessels running the length of the body, running the length of the body, connected by the 5 pseudohearts which pump the blood

single system

where blood passes through then heart once

double system

where blood passes throigh the heart twice and there re seperated systemic body and pulmonary systems

Three layers in blood vessels

-tough collagen

-elastic muscular layer to sustain pressure

-endothelium which is smooth to reduce friction

Arteries

thick walls to resist high pressure. They are able to adjust diameter to adjust blood supply and blood pressure

label artery and vein

veins

thinner muscle layer than arteries

-larger diameter than arteries

-reduced pressure compared to arteries

valves to flow in one direction only

capillaries

-walls are one layer thick and permeable

-small diameter

friction in walls slow down blood flow

-many capillaries in a bed for a large total crosssectional area, which further reduces blood flow

-low velocity to enhance ability to exchnage materials with surrounding tissue

-gaps that allow exchange of material

capillary

heart

cardiac muscle

intercolated discs, branched, faintly striated. MYOGENIC

the cardiac cycle

1- diastole, atria and ventricles relax and blood enters heart

2- atrial systole, atria contract and ventricle react, blood enters ventricle

3-ventricular systole, ventricle contracts and blood is forced out of heart.

more detailed heargt

How does the heart contract

the SAN sends a wave of excitation across the atria causing them to contract at the same time

This is prevented from spreading to the ventricles by a thin layer of connective tissue

Instead it spreads via the atrioventricular node, through the bundle of His to the apex of the ventricle . This branches into the Purkinje fibres which carry the wave of excitation through the ventricle muscle .

What does LVEDV mean

left ventricular end diastoli volume (volume of blood in the ventricle at the end of filling)

What does LVP mean

left ventricular pressure

LVESV

left ventricular end systolic volume (volume of blood in the ventricle at the end of emptying)

graphs

What are electrocardiograms

the electrical activity through the heart can be detected using electrodes

What does a ECT wave (healthy) look like

What does the P wave on an ECG show

the depolarisation of the atria during atrial systole

What does QRS wave on an ECG show

the spread of depolarisation through the ventricles resulting in ventricular systole

What does the T wave in an ECG diagram show

the repolarization of the ventricles during ventricular siastole

Where is blood pressure the highest and what does ti show

in the aorta and main arteries, showing rhythmic rise and fall corresponding to ventricukar contraction

Why does blood pressure drop as it moves away from the heart?

friction between blood cells and vessel walls as blood flows further from the heart

How do arterioles and capilleries affect blood flow?

large total surface area and narrow bore create high resistance. Lowers aortic pressur and slows down blood flow.

Whats the relationship between blood velocity, pressure and capillary beds?

velocity is directly related to pressure

Return flow to the heart

non-rhythmic. Pressure in veins is low but can be increased by the massaging effect of the muscles

red blood cells

erythrocytes

white blood cells

leucocytes

1-Granulocytes- granular cytoplasm and lobved nucleis. Phagocytic

2-agranulocytes- clear cytoplasm and spherical nuclei. produce antibodies

adaptations of Erythrocytes

-biconcave discs- large SA:V, flexible to pass through capilleries

-Haemoglobin- carries 12x more oxygen

-no nuceleus- more volume for Hb

Haemoglobin structure

4 subunits of a polypeptiude chain surrounding a haem gorup

Each haem group can carry one oxygen molecule