14. CHARACTERISTIC PRESSURES IN THE BODY (PART 2) Flashcards
1
Q
- What is one way to directly measure pressure?
A
- with a Manometer
2
Q
- What is the measured pressure in the Manometer corresponding with?
A
- the height of the fluid column
PLUS - the reference pressure
THEREFORE:
P = Preference + pgh
3
Q
- When is the Manometer commonly used?
A
- it is commonly used to measure small and moderate pressure differences
4
Q
- What does a Manometer usually contain?
A
- one or more fluids
- such as:
- mercury
- water
- alcohol
- oil
LOOKING AT THE IMAGE:
At point 1 and 2
- the pressures are equal
- this is due to Pascal’s Law
- there is a force existent due to the Pressure
5
Q
- What is the most common way to measure blood pressure?
A
- with the use of a Sphygmomanometer
6
Q
- What does a Sphygmomanometer consist of?
A
- a cuff
- a squeeze bulb
- a mater
- all of this measures the pressure in the cuff
7
Q
- What are the two types of Pressure Gauges used in Sphygmomanometers?
A
- Mercury Manometer
- Aneroid Manometer
8
Q
- How is pressure indicated in a Mercury manometer?
A
- the pressure is indicated by the height of the column of mercury inside the glass
9
Q
- How is the pressure measured in an Aneroid Manometer?
A
- the pressure changes the shape of the sealed flexible container
- this causes the needle to move on the dial
10
Q
- What can act as a crude pressure indicator?
A
- specific parts of the body
11
Q
- Provide two examples where parts of the body act as Crude Pressure Indicators?
A
- A PERSON IN AN AIRPLANE:
- will feel the changes in atmospheric pressure
- in their ears - THE SIZE OF THE VEINS AT THE BACK OF THE HAND:
- as the hand is slightly raised above the level of the
heart
- these veins become smaller
- this is due to a lower venous blood pressure
- it is more difficult to pump the pressure up
- the pressure will fluctuate
12
Q
- in every heart beat cycle (1/s), what can be said about the variations in the blood pressure in the major arteries?
A
- the blood pressure in the major arteries varies
between:
- 120 mmHg (Systolic)
- 80 mmHg (Diastolic)
13
Q
- What happens when the pressure in the Aneroid Manometer cuff exceeds the Systolic Pressure?
A
- there is no blood flow to the lower arm
- there are no sounds that can be heard
14
Q
- What happens when the pressure in the Aneroid Manometer cuff is lowered with the release bulb to just below the Systolic Pressure?
A
- there is now intermittent flow of blood
- the flow fluctuates
- sound is now produced
15
Q
- What is the pattern of the blood flow when using an Aneroid Manometer?
A
- Smooth
- Turbulent
- Transitional
16
Q
- What does the intermittent flow produce because it is Turbulent?
A
- gurgling sounds
- these are called Korotkoff
- also known as K Sounds
17
Q
- What happens to the K Sounds as the Aneroid Manometer cuff pressure is lowered?
A
- the K sounds become louder
- and then they become lower
- they continue to be heard until the cuff pressure
decreases to the diastolic pressure
18
Q
- What happens to the K Sounds as the blood flow is no longer interrupted?
A
- the K Sounds cease
- this is because the blood flow is no longer turbulent
19
Q
- What denotes the Systolic and Diastolic Blood Pressures?
A
- the onset and the end of the K Sounds
20
Q
- What does the Brain consist of?
A
- approximately 150 cm³ of Cerebrospinal Fluid (CSF)
- these are found in a series of interconnected openings
(ventricles)
21
Q
- What happens if there is a block in the ventricles at birth?
A
- the Cerebral Spinal Fluid is trapped inside the skull
- this increases the internal pressure
- this increased pressure causes the skull to enlarge
- a condition known as Hydrocephalus
22
Q
- How can Hydrocephalus be detected?
A
- the Cerebral Spinal Fluid cannot be measured directly
THEREFORE:
- we measure the circumference of the skull
- just above the ears
23
Q
- What is the function of the clear fluid in the eyeball?
A
- it transmits the light to the retina
- it is kept under a specific pressure
- it maintains the eyeball in a fixed shape and size
24
Q
- What is the pressure range for the normal eye?
A
- it ranges from 1.6 to 3 kPa
25
Q
- What happens if the pressure increases in the Eyeball?
A
- it can restrict the blood supply to the Retina
- this will affect vision
- this condition is called Glaucoma
26
Q
- How is the pressure in the eye measured?
A
- with Tonometers
- these measure the amount of indentation produced by a known force
27
Q
- Which pressure is larger than the atmospheric pressure?
A
- the pressure is most of the gastrointestinal system
28
Q
- What can be said about the Pressure in the Oesophagus?
A
- the pressure is coupled to the pressure between the lungs and the chest wall
- this is known as Intrathoracic Pressure
(this is usually less than Atmospheric Pressure)
29
Q
- How is the Intrathoracic Pressure sometimes determined?
A
- by measuring the pressure in the Oesophagus
30
Q
- What happens to the pressure in the stomach when we eat?
A
- the pressure in the stomach increases as the walls of the stomach are stretched
- this is mostly due to the air being swallowed during eating
31
Q
31.What does air trapped in the stomach cause?
A
- burping
- belching
- this air can be seen on an X-Ray of the chest
32
Q
- What generates gas in the gut?
A
- the bacterial action increases the pressure
- this generates gas
- gas is also known as flatus
- external factors can affect gut pressures
(such as belts)
33
Q
- Where are the highest pressures in the body found?
A
- in the weight bearing joints
- these pressures are called: STRESSES
34
Q
- What is the stress on the Knee Joint when all the weight of one leg is placed on the Joint?
A
- it may be more than 10⁶ Pascals
- this is equal to 10 atm
(atmospheric pressures)
35
Q
- What aspect of the joints prevents the stress that they experience from being even higher?
A
- the relatively large area
36
Q
- What is one of the most noticeable Internal pressures in the body?
A
- the pressure in the bladder
- this is a result of the accumulation of urine
37
Q
- What is Cystometry?
A
- a clinical diagnostic procedure
- it is used to measure the forces in the bladder
38
Q
- What does a Cystometrogram plot?
A
- it plots the volume of the liquid
against the intravesicular pressure
39
Q
- When does bladder pressure increase?
A
- during coughing
- during sneezing
- during straining
- during sitting up
- during a stressful situation
- during pregnancy
- when the weight of the foetus over the bladder increases the pressure
- this also causes frequent urination
40
Q
- Read through Summary 1.
Does everything make sense?
A
- yes
41
Q
- Read through Summary 2.
Does everything make sense?
A
- yes
42
Q
- Read through Summary 3.
Does everything make sense?
A
- yes
43
Q
- Read through Summary 4.
Does everything make sense?
A
- yes