Biology topic 1

Right side recieves

Deoxygenated blood

Left side recieves

Oxygenated blood

Right side pumps to

Lungs

Left side pumps to

Body

Coronary artery function

Supply the cardiac muscles with nutrients for respiration

Coronary vein function

Return deoxygenated blood back to heart muscle

Walls of heart made of

Cardiac muscle

Cardiac cycle

Sequence of events from one heartbeat to the next heartbeat with three phases

Three stages of cardiac cycle

Diastole

Atrial systole

Ventricular systole

What part of heart involved in diastole? Contract or relaxes?

Atria and ventricles relax

Which valves are open and closed in diastole

Semifinal closed, atrioventricular sometimes open

Where is movement of blood in diastole

Blood enters atria which passively goes into the ventricles. Coronary arteries fill during diastole top

Part of heart involved in atrial systole? Contract or relax?

Atria walls contract

Valves open and closed in atrial systole

Atrioventricular open, semilunar closed

Movement of blood in atrial systole

Atria to ventricles

Part of heart involved in ventricular systole? Contract or relax?

Ventricles contract

Valves open and closed in ventricular systole

Atrioventricular close and semilunad open

Movement of blood in ventricular systole

Ventricles to pulmonary artery and aorta

Why do we need a heart

• To generate pressure and pump blood around the body

• to overcome limitations of diffusion to ensure fast delivery of oxygen to body cells

Why is left side of heart thicker

Contains more muscle to generate higher blood pressure to pump blood further distance

What is in the centre of the heart to stop the sides mixing

Septum

What are the 3 blood vessels

Vein, artery and capillaries

Mass transport system

Substances transported in the flow of a fluid with a mechanism for moving the fluid around the heart

Good transport system needs

• Fluid to carry nutrients and oxygen

• Pump to push fluid around body

• Exchange surfaces

Factors that effect need for transport systems

• Size (SA:V ratio)

• Metabolic rate and activity level

• How animals keep warm

3 types of circulatory system and examples

Open -insects

Closed, single - fish

Closed, double- mammals

Stage 1 and 2 of diastole

1. Atria and ventricles relax

2. Blood flows into the atria from veins. Elastic recoil of atrial walla generates low pressure in atria helping to draw blood into heart

Stage 3,4 and 5 of diastole

3. Under influence of gravity, blood in arteries flows down towards ventricles closing the semilunar valves

4. Atria fill with blood

5. Pressure in atria increases pushing open atrioventricular valves

Stage 6 and 7 in atrial systole

6. Blood flows into relaxing ventricles

7. Both atria contract

Stage 8 and 9 in ventricular systole

8. Remaining blood is forced through atrioventricular valves into the ventricles

9. Ventricles contract after slight delay

Stage 10 and 11 in ventricular systole

10. Pressure in ventricles increases and blood us forced upwards, closing the atrioventricular valves

11. Blood is forced into the aorta and pulmonary artery, opening the semilunar valves

Why are sides of heart seperate

• Steep concentration gradient fir faster diffusion

• Maximum oxygen carried by mass flow

• Maintains pressures for more efficient delivery of oxygen and lower in lungs to not damage it

Parts of artery

• Outer collagen coat

• Thick muscular wall

• Thick smooth muscle

• Thick elastic fibre

• Smooth endothelial

• Narrow lumen

• No valves

Parts of vein

• Outer collagen coat

• Smooth endothelium

• Wide lumen

• Thin smooth muscle

• Thin elastic fibre

• Valves

Parts of vein

• Outer collagen coat

• Smooth endothelium

• Wide lumen

• Valves

• Thin smooth muscle

• Thin elastic fibre

• Valves

Why does artery have thick muscular wall

To withstand highblood pressure

Why does artery have collagen coat

Strength to prevent artery bursting and to withstand high blood pressure

Why does artery have thick smooth muscle

It contracts to constrict artery to maintain blood pressure

Why does artery have thick elastic fibre

Allow artery to stretch and recoil to squeeze blood forward and maintain blood pressure

Why does artery have smooth endothelium

Reduces friction

Why does artery have narrow lumen

Maintain high blood pressure

Why does artery not have valves

Blood is always forced forward by heart contraction and elastic recoil

Why does vein have collagen

Strength

Why does vein have smooth endothelium

Reduces resistance to blood flow

Why does vein have wide lumen

Make vessel easier to squeeze between skeletal muscles

Why do veins have valves

Prevent backflow

Why do veins have thin smooth muscle

Less ability fo4 comtraction to constrict blood vessel

Why does vein have thin elastic fibre

Less elastic recoil

Why capillary wall only 1 cell thick

Help exchange of dissolved substances between blood and cells by reducing diffusion distance

Why does capillary have very narrow lumen

• Slows flow of blood to allow time for exchange more efficiently

• Walls of blood cell in contact with wall to reduce diffusion distance

Why do capillaries have tiny holes in their walls

Allow passage of materials through wall into tissue fluid

What is an open circulatory system

Blood held in organ cavity and organs are bathed in blood

Pressure in open circulatory system

Low

What is closed circulatory system

Blood held in blood vessels

Pressure in closed circulatory system

High

Blood pressure when reaching body capillaries in single circulatory system,

Low pressure

Blood pressure when reaching body cappilaries in double circulatory system

High pressure

Where is blood pumped in single circulatory system

To gills then around rest of body then back to heart

Where is blood pumped in double circulatory system

Lungs then back to heart which pumps oxygenated blood through aorta to rest of body then returned to heart by vena cava

Repressurisation

Blood gets an extra boost when returns from lungs to heart to allow heart to pump oxygenated blood at higher pressure to body

Why do animals need circulatory system

• Low sa:v ratio

• Diffusion isn’t efficient

• Circulatory system carries oxygen and nutrients around body

Why do organisms need mass transport system

To move molecules quickly between gas exchange surfaces and cells in organisms that have smaller sa:v ratio where diffusion is inadequate

What is water made of

1 oxygen and 2 hydrogen

Charge on water molecule

Hydrogen slightly positively charged

Oxygen slightly negatively charged

How do water molecules join

The slightly positive charged is attracted to the slightly negative ends of surrounding water molecules

Why can molecules dissolve in water

Dipole nature of water

Hydrophobic

Water loving (polar) substances that dissolve

Hydrophobic

Water hating (non polar) substances that don’t dissolve

Specific heat capacity

Amount of energy required to raise temp of 1cm³ of water by 1°c

Why is specific heat capacity so high

Large amount of energy required to break hydrogen bonds

Another name for blood clot

Thrombus

Why do blood clots form

• Minimise blood loss

• Prevent pathogens entering

How do blood clots form

1. Platelets stick to damaged blood vessel. Thromboplastin produced by platelets and damaged tissue

2. Thromboplastin in presence of calcium ions and vitamin k converts prothrombin to thrombin

3. Thrombin converts fibrinogen to fibrin which causes mesh of insoluble fibre

4. Mesh traps platelets and red blood cells forming blood clot

What does thromboplastin with calcium ions and vitamin k do

Convert prothrombin to thrombin

What does thrombin do

Convert fibrinogen into fibrin

What does fibrin do

Forms mesh of insoluble fibres which traps platelets and red blood cells causing blood clot

What us atherosclerosis

Hardening of arteries

Main risk factors if atherosclerosis

Coronary heart disease and stroke

How is atherosclerosis formed

1. Damage to endothelium triggers inflammatory response where white blood cells accumulate and cholesterol enters blood vessel

2. Causes fatty buildup called atheroma

3. Calcium salts and fibrous tissue build up resulting in plaque

4. Cause artery to lose elasticity and harden

5. Lumen narrows which increase blood pressure

Atherosclerosis positive or negative feedback

Positive feedback because increases blood pressure which causes more damage to endothelium

What causes damage to endothelium

• High blood pressure

• Toxins from cigarette smoke

• Infections such as chlamydia

What is blood pressure a measure of

The hydrostatic force of the blood against the walls of a blood vessel

elevated blood pressure known as

Hypertension

Systolic pressure

Maximum blood pressure when heart contracts in ventricular systole

Diastolic pressure

Lowest blood pressure when heart relaxes in diastole

Peripheral resistance

Contact between blood and walls of blood vessel causes friction which slows blood flow

Where is peripheral resistance strongest

Vein

Where is peripheral resistance lowest

Artieries

Healthy systolic blood pressure

100-140mmHg

Healthy diastolic blood pressure

60-90mmHg

Oedema

Fluid build up in tissues and causing swelling

Oedema forms

• Tissue fluid forms when plasma is forced put of capillaries, carrying with it nutrients and oxygen

• Cells absorb nutrients and oxygen from tissue fluid and give out waste

• Tissue fluid moves back into capillaries by osmosis

• 20% of tissue fluid drains into blind ended lymph capillaries. It flows through lymph vessels and returns thr lymph fluid to the blood via the thoriac duct in the neck

How is tissue fluid formed

When plasma is forced out of the capillaries, carrying with it nutrients and oxygen

What happens to tissue fluid that isnt reabsorbed

It drains into blind ended lumph capillaries. It flows through the lymph vessels and return thr lymph fluid to thrblood via the thoracic duct in thr neck

How much tissue fluid isn’t reabsorbed

20%

3 monosaccharides

Glucose, galactose, fructose

3 disaccharides

Maltose, sucrose, lactose

Bond which joins monosaccharides

Glycosidic bond

General formula for monosaccharides

(CH20)n

Which two polysaccharides make starch

Amylose and amylopectin