Mass transport -circulatory system (copy)

How is the pressure in the chamber increased

The chamber contracting

Volume of blood inside the chamber increasing

What is the cardiac cycle

The complete cycle of the heart beating

Includes diastole ,atrial systole and ventricular systole

How do valves work

Open when pressure behind the valve is higher than in front

Closes when pressure behind is lower than front

Prevents the back flow of blood

Explaim in terms of pressure why the semilunar valves open

Pressure is higher in the right ventricle compared to the pulmonary artery so they open because pressure behind The valve is higher

Explain how the heart strings maintain blood flow in one direction of the heart

Valves close due to high blood pressure when ventricles contract

Prevents valves from being inverted

Explain atrial systole

The atria muscle wall contracts

Space/volume inside the atria decreases

Pressure in atria increases

So more blood moves from the atria to the ventricles

Because atrioventricular valves open

So volume of blood in the ventricles increases

Explain ventricular systole

Ventricle muscular walls contract

Space inside/volume the ventricles decreases

Pressure increases

Atrioventricular valve closes

The pressure in the ventricles is higher than the arteries

So the semi lunar valve opens so blood moved out of ventricle down pressure gradient

Explain diastole

Atria and ventricular muscles are relaxed

Blood will enter the atria via vena cava and pulmonary vein

Blood flowing into atria increases within atria

What is the heart rate

Heart beats per minute

What is the equation for cardiac output

Cardiac output (dm3/min)=heart rate x stroke volume

What is the stroke volume

Blood pumped out of the ventricle per beat

Explain why an athletes heart rate is low but cardiac output is the same

Stroke volume increases

Increased size of ventricles

More heart muscle

Stronger contraction

How to convert from dm3 to cm3

X1000

How do you calculate the size of the lumen

Blood vessel diameter-thickness of walls x 2

What is the function of coronary arteries

Supplies the cells of the heart with blood which brings them oxygen and glucose

Explain how blood pressure is generated in the arteries

Blood pressure is generated by contraction of the left ventricle

Explain the function and adaptation of the arteries

Function-supplies body cells with oxygen and glucose from the blood

-thick muscular walls=withstand high pressure

-smooth inner layer=reduces friction and allows for fast movement of blood

-elastic tissue

Explain how arteries elastic wall affects pressure

Must be elastic,decreases fluctuations in blood pressure

During ventricular contraction,when pressure increases and heart beats,wall stretches and becomes thinner and reduces increase in pressure

During ventricular relaxation the pressure decrease artery wall recoils and becomes thicker,reduces decrease in pressure

Endothelium smooth to reduce friction

Explain the function and adaptations of arterioles

Function-takes blood from artery to capillary,controls amount of blood flow

Thinner elastic layer -less fluctuations in blood pressure

Thicker smooth muscle (other flashcard )

Explain why arterioles have thicker smooth muscle

Contracts and relaxes to control and change blood flow into capillaries

When smooth muscle relaxes,arterioles dilate so the lumen diamester increases blood flow increases (more oxygen and glucose for respiration,atp,muscle contraction)and there is increased cross sectional area

When smooth muscle contracts arterioles constrict so the lumen becomes diameter decreases .flow decreases and there is a decreased cross sectional area

Explain why there is difference in pressure of blood between the pulmonary vein and aorta/what causes difference

Left ventricle has a thicker wall/more muscle

So left ventricle contracts more forcefully

Explain the adaptations Of the capillaries to maximise gas exchange

Permeable membrane

Walls are single cell thick +flattened/endothelial so short diffusion pathway

Small diameter gives short diffusion pathway/ larger SA:volume

Narrow lumen-reduces rate of flow giving more time for diffusion

Red blood cells in contact with wall gives short diffusion pathway

Fenestrations allow molecules through

Suggest why the pulse felt can be used to measure heart rate

Caused by pressure/surge of blood

From one contraction of left ventricle

Explain the function and adaptation of the veins

-transports blood into the heart

Wider lumen/larger diameter

Valves along whole length,most arteries do not gave valves along whole length

Thinner walls because less muscle and less elastic tissue,does not need to withstand pressure

Describe how valves prevent the back flow of blood

Pressure builds from blood being pushed by heart.increase in pressure behind the valve lushes it open and blood flows through.

If pressure falls behind the valve.pockets fill and close the valve

Describe how the veins move blood up

Body muscle contracts

Squeezing the walls of veins

Decreasing the volume of space in veins

Increasing pressure

Blood travels upwards down a pressure gradient

Valves prevent back flow

Describe differences in structure of the aorta and vena cava

Aorta has a thicker wall than vena cave

Aorta has a narrower lumen than vena cava

Aorta contains thicker/mkre smooth muscle than vena cava

Aorta contains more /thicker elastic tissue than vena cava

Vena cava has valves along its length but aorta only has semi lunar valves

What is tissue fluid

Fluid that bathes all cells

Formed by substances leaving the blood at the capillaries

Describe what happens at the arterial end of the capillary

• There is a high hydrostatic pressure caused by contraction of the ventricles

• .The hydrostatic pressure is higher in the capillary compared to the tissue fluid .Greater than osmotic pressure+WP

• Water and small solute are forced out (Ultrafiltration)

• Red blood cells,large soluble proteins and ions remain in the capillary because they are too large

Describe what happens and the venal end of the capillary

• There is a lower hydrostatic pressure than the arterial end and fluid has left capillary

• there is a low water potential due to large insoluble proteins that remain

• Osmotic presssure /water potential is higher than hydrostatic pressure

• There is a net movement of water into the capillary from the tissue fluid by osmosis

  
  

Water potential of the blood plasma is more negative at the venue end than the arterioles end explain why

Water has left the caplillary

Proteins are too large to leave capillary

Higher concentration of blood proteins/low water potential

How can a lack of protein in the blood cause a build up of fluid

Less protein =less protein in the blood

Fewer large soluble proteins

Water potential at the venue end is higher than tissue fluid

Decrease in water deist

No osmosis of water back into the capillary

How is tissue fluid drained by lymphatic system

• Excess fluid is absorbed by the lymphatic capillaries.this eventually returns to the blood at the subclavian vein

What is haemoglobin

The haemoglobins are a group of chemically similar molecules found in many different organisms.haemoglobin is a protein with a quaternary structure

Transports oxygen around the body

Describe the structure of haemoglobin

Quaternary structure

Four polypeptide chains 2a 2b

Four haem groups which contain fe 2+ions

Describe red blood cells adaptationsn

Flexible biconcave disks

Do not have nucleus

Do not carry most organelles to accommodate maximum space for haemoglobin

Describe how haemoglobin can transport oxygen

Loading +unloading can occur because haemoglobin can change its tertiary structure ,when this happens affinity changes

It becomes easier to load oxygen when it has a more open shape because haem groups are uncovered and more oxygen binds,affinity increases

Why is fetal haemoglobin different to adult why is this beneficial

Useful across the placenta,different primary strfutre to different tertiary structure,changes so there is a higher affinity for oxygen at the same partial pressure

Adult haemoglobin will unload and fetal haemoglobin will,load so oxygen is passed from mum to baby

Why does fetal hb - he have a higher affinity

Higher affinity for oxygen means more oxygen can load at the same partial pressure so oxygen moves from mother to foetus

How does the Bohr effect affect oxygen dissociation during excersie

• More respiration and co2 production during excercise

• CO2 dissolves in water to make carbonic acid

• Ph in the blood decreases due to carbonic acid ,tertiary strfutre of haemoglobin changes because hydrogen and ionic bonds on r groups change

• Affinity decreases and more oxygen unloads

• Oxygen is used by respiring tissues to produce ATP for muscle contraction

Explain how the S shape of the dissociation curve provides evidence that the first oxygen molecule makes it easier for others to bind

At low partial pressure of oxygen an increase in partial pressure only results in a small increase of HB saturation with oxygen

As ppo2 increases there is a rapid increase in the saturation of Hb with oxygen

Because HB has a higher affinity for o2 so oxygen binds more easily

Why might an ice fish lack haemoglobin

Very low temperatures

Respiration rates low

Low oxygen demands

Rely on water alone to transport their oxygen

Explain how oxygen is loaded transported and unloaded in the blood

Haemoglobin carries oxygen

In red blood cells

It loads in the lungs at high partial pressure

Unloads /releases to respiring tissues at low partial pressure

Explain the type of haemoglobin an active organism has and why

Has a high rate of respiration so requires a lot of oxygen +is energy demanding

The haemoglobin has a lower affinity in order to release oxygen more readily so animals tissues can respire rapidly

Explain the type of haemoglobin a less active organism has and why

Is less active,moves less and respires less so does not require as much oxygen

Haemoglobin has a higher affinity for oxygen to load more as it does not need to be used

Explain the type of haemoglobin a smaller sized mammal has and why

SA:volume ratio is large so more heat loss per unit of body mass in cooler environment .

HB lower affinity for oxygen so tissues can respire more and produce more heat which helps to maintain the temperature of animal

Explain the type of haemoglobin an animal that lives in a high altitude has and why

Atmospheric pressure is lower and partial pressure of oxygen is lower

More difficult to load haemoglobin with oxygen

HB has a greater affinity for oxygen so it can load oxygen more easily at lower partial pressure