Download Topic 1.3a Age, Gender and Blood Pressure File

Age, Gender and
Blood Pressure
Specification- topic 1
12 Describe the factors that increase the risk of CVD (genetic, diet, age, gender, high blood
pressure, smoking and inactivity).
Risk Factor- Age and gender
• Read page 24-25
• Answer Q 1.13 to 1.17
• Activity 1.11 Analysis of Cardiovascular Disease Data- Q 1-6, 8
Risk Factor- High blood
pressure
• What is blood pressure? Read page 26
• Hydrostatic force of blood pushing against the walls of the blood
vessels.
• Measured using a sphygmomanometer and stethoscope or a blood
pressure monitor
• The result is expressed as- systolic pressure/diastolic pressure
• Systolic pressure- pressure peak in the arteries which occurs during
ventricular systole
• Diastolic pressure- pressure minimum in the arteries which occurs
during diastole
• Normal range is• 100- 140mm Hg (sytolic pressure)
• 60- 90 mm Hg (diastolic pressure)
• Complete Activity 1.12 Measuring Blood Pressure- SNAB interative
tutorial
Recording Our Blood Pressure
Name
Blood Pressure
What determines the blood pressure?
• Read page 27
• Peripheral Resistance
• Cardiac output
• Pulse rate• number of beats per minute
• Stroke volume• volume of blood pumped out of the
ventricles in one beat
• Cardiac output = pulse rate X stroke volume
• If the cardiac output increases the blood
pressure will ______________.
•
•
Look at figure 1.25 on page 27. Why does pressure
decrease?
• Along the arterioles and capillaries there is a high
surface area
•
Peripheral resistance (due to friction due to the high
surface area)
•
Blood slows down as it goes further from the heart
• Blood Pressure decreases
What causes fluctuations?
• Contraction and relaxation of the heart.
• Elastic recoil of the artery walls
What is the function of the muscle tissue in the arteries?
It can constrict and dilate, altering blood flow.
• Arteries Constrict
• Arteries Dilate
• Peripheral resistance
increases due to
decreased
volume/space
• Peripheral Resistance
decreases due to
increased volume/
space
• Blood pressure
increases
• Blood pressure
decrease
Other factors which affect the blood pressure
• Which factors can increase BP long-term by causing the
arteries to constrict long-term? Explain. See also page 47
• Loss of elasticity with age so lower volume/space in
arteries increasing the b.p.
• High salt diet- increases the volume of blood due to
more water kept by the kidney so higher b.p.
• Adrenaline- arteries and arterioles constrict raising b.p.
• What is another way in which adrenaline increases the
blood pressure?
• It increases the cardiac output so also increases the
B.P.
• Complete Activity 1.13
What is one symptom/sign of high b.p.?
• Oedema:
• What is it?
• excess tissue fluid
• What causes it?
• formed due to hypertension forcing more fluid out of the
capillaries than is drawn back in. This causes swelling.
What is tissue fluid? Read page 28
• Also called Interstitial fluid
• Surrounds tissue and allows diffusion between itself (tissue fluid)
and cells.
• Formed from plasma which leaks out of capillary walls.
How does tissue fluid form? Study figure 1.26
• Hydrostatic pressure- what is it and at which end of the capillaries is
it higher?
• blood pushing against the walls of the blood vessels.
• Highest at the arteriole end
• Osmotic pressure- the pressure exerted by water as it moves by
osmosis.
• What determines the direction and rate of osmosis?
• Water moves from a high to a low water potential
• The steeper the water potential gradient the faster the
rate of osmosis
• How are capillaries adapted to enable the formation of tissue fluid?
• Lining / wall one cell thick ;
• Lining/wall made of thin cells;
• Pores ;
• Selectively / partially permeable ;
Complete Tissue Fluid Formation
Tissue Fluid Formation
• Add arrows to identify the following at the arteriole end AND the venule end (draw wider
arrows to identify the stronger forces)• Direction hydrostatic pressure is exerted
• Direction osmotic pressure is exerted
• Draw conclusions from your answers to # 3 in order to add arrows to identify the
following• Direction of net flow of water and solutes at the arteriole end
• Direction of net flow of water and solutes at the venule end
•
•
•
•
Tissue Fluid Summary
At the arterial end of the capillary the hydrostatic
pressure is greater than the osmotic pressure, so fluid
flows out of the capillary.
At the venule end of the capillary the osmotic
pressure is greater than the hydrostatic pressure, so
fluid flows into the capillary.
Lymphatic system: excess tissue fluid drains into the
lymphatic system (lymph nodes and lymph vessels).
Lymphatic system is part of the immune system, we
will discuss the lymphatic system later but know that
it contains structures dedicated to the production of
lymphocytes, white blood cells.
Specification- topic 1
12 Describe the factors that increase the risk of CVD (genetic, diet, age, gender, high blood
pressure, smoking and inactivity).