Describe the physiological processes that allow for blood pressure measurements to be taken using sphygmomanometry (Korotkoff sounds, arterial turbulence, etc.)
- brachial artery occluded by cuff - no sound heard with stethescope
- pressure lowered slowly
- at point when systolic pressue in artery just exceeds the cuff pressure a spurt of blood passes through with each heartbeat - this is heard with stethescope as a tapping sound, the first sound is the systolic pressure
- sounds become louder, then dull and muffled - sounds of Korotkoff
- then (most people) sounds disappear - diastolic pressure with they disappear
- *Adults after exercise and children, diastolic pressure is when the sound becomes muffled, or in disease such as hyperthyroidism and aortic insufficiencey
because of cuff pressure -blood produces turbulent flow which is why it can be heard - Korotkoff sounds
Perform sphygmomanometric, pulse rate, respiratory rate and temperature measurements and discuss the effects that changes to accepted technique have on the precision of these measurements.
changes from these techniques would result in improper measurements
Describe mean arterial pressure (MAP) and discuss factors determining MAP.
Average pressure throughout the cardiac cycle
slightly less than value of half-way because systole is shorter than diastole
area under the pressure curve - mathematically it is approximately diastolic pressure plus 1/3 pulse pressure
(pulse pressure is systolic - diastolic pressures)
Predict the changes in blood pressure based on changes to blood volume, peripheral resistance, mineralocorticoid excess, adrenergic stimulation.
increased blood volume - increased BP
increased peripheral resistance - increased BP
mineralocorticoid excess…increased BP (pretty sure…might want to double check that one)
increased adrenergic stim - increased BP
Describe the neural regulation of BP: baroreceptor reflex as primary homeostatic control of BP.
Baroreceptors stimulated by distension of structures in which they are located - sensitive to pulsatile pressures rather than constant
discharge at increased rates when pressure rises
afferent fibers pass via the glossophayngeal and vagus nerves to medulla … inhibits discharge of the sympathetic nerves and excites the vagl innervation of the heart.
produce vasodilation, venodilation, hypotension, bradycardia and decresed CO
decrease in pressure, decrease discharge rate of baroreceptors and provokes rise in systemic BP and tachycardia
Baroreceptors on arterial side of circulation, their afferent connections to the medullary cardiovascular areas and the afferent pathways from these areas constitue a reflex feedback mechanism that opperates to stabilize BP and HR
drop in arterial pressure - decreased discharge in buffer nerves - rise in BP and CO
rise in pressure - dilation of arterioles and decreased CO until BP reurns to previous baseline
Describe the location of baroreceptors and explain how they are involved in the regulation of BP.
…in cardiovascular cue cards…
Describe the local autoregulatory mechanisms that exist for local blood pressure control.
…in cardiovascular cue cards…
Perform vitals, and understand the physiological implications behind normal and abnormal findings.
physiological mechanisms …?
Demonstrate proper technique in measuring blood pressure using a sphygmomanometer and identify normal and abnormal findings
normal findings would be a blood pressure between 90/60 to 120/80 mmHg
Describe how indirect estimation of blood pressure is measured with a sphygmomanometer to give estimates of systolic and diastolic pressures
Wrap the cuff around the patient’s arm with the artery index marker in line with the patient’s brachial artery. The writing on the cuff should be visible (not against the patient’s skin). The cuff should be tight enough so that the cuff does not slide off the arm and two fingers should be difficult to get between the cuff and the patient’s arm.
Attach the cuff to the manometer.
Find the patient’s radial arterial pulse with one hand and inflate the cuff by squeezing the bulb of the manometer with the other hand. Notice the pressure that coincides with the disappearance of the radial pulse.
Completely deflate the cuff.
Ask the patient to raise their arm and open and close a fist ten times
While supporting the patient’s arm at heart level, place the diaphragm of the stethoscope over the brachial artery and inflate the cuff again 20mmHg beyond the pressure noted previously that coincided with the disappearance of the radial arterial pulse.
Release the valve so that the pressure in the cuff drops by about 1-2 mmHg per second and listen for the first sound of blood. This is the systolic blood pressure.
Continue listening until the sound disappears. This is the diastolic blood pressure.
Completely deflate the cuff and remove from patient’s arm.
The arm the measurement was taken and the position of the patient during measurement (standing, sitting, lying) should be recorded.
Given systolic and diastolic blood pressures, calculate the pulse pressure and the mean arterial pressure
pulse pressure = systolic - diastolic
mean pressure = diastolic + 1/3 pulse pressure
Predict the changes in arterial systolic, diastolic, mean and pulse pressures based on changes in a) stroke volume, b) heart rate, c) arterial compliance, and d) total peripheral resistance.
systolic a) increased = increased b) increased = ??? c) increased = decreased d) increased = increased diastolic a) increased = ??? b) increased = ??? c) increased = decreased d) increased = increased mean a) increased = increased b) increased = increased c) increased = decreased d) increased = increased pulse a) increased = ??? b) increased = ??? c) increased = decreased d) increased = increased
Demonstrate proper technique in assessing heart rate and rhythm, and identify normal and abnormal findings.
normal = 60-100bpm
Demonstrate proper technique in assessing respiration rate, and identify normal and abnormal findings.
normal = 12-18 breaths/min
Identify the regions in the CNS that play important roles in the generation and control of cyclic breathing.
voluntary control is located in the cerebral cortex and sends impulses to the respiratpry motor neurons via the corticospinal tracts
automatic control is in the medulla
-pacemaker cells in the medulla - impulses from these cells activate motor neurons in the cervical (diaphragm via phrenic nerve) and thoracic (external intercostal muscles) that innervate respiratory muscles
main components of respiratory control pattern generator are located in the medulla
rhythmic respiration is initiated by a small group of synaptically coupled pace-maker cells in the pre-Botzinger complex
rhythmic discharge is modified by neurons in the pons and afferents in the vagus from reseptros in the airways and lungs
Describe the reflex control of ventilation.
rise in PCO2 or H+ or drop in PO2 of arterial blood increases level of respiratory neuron activity in the medulla resulting in incrased respiration - opposite changes are inhibitory = decreased respiration
chemoreceptors are in the carotid and aoritc bodies, collections of cells in the medulla and elsewhere are sensitive to changes in the chemistry of the blood
Carotid and aortic bodies contributing to reflex control of respiration
type I cells (glomus cells) have O2-sensitive K+ channels
-as PO2 decreases - K+ conductance decreases - reducing K+ effluc causing cellular depolarization - activate L-type calcium channels - Ca2+ influx - action potential and neurotransmitter release
medullary chemoreceptors and reflex control of respiration
monitor H+ in blood
-CO2 readily penetrates BBB - CO2 hydrated to H2CO3 - dissociates - increased H+
Recall the adult normal ranges for blood pressure, temperature (in degrees C), pulse rate, respiratory rate.
BP: 60/90 - 120/80 mmHg
RR: 12-18 breaths/minute
Temperature: 35.8-37.9 degrees Celsius
Identify the body areas used to take temperature and describe the pros and cons of each area in terms of estimation of core body temperature
Oral - is standard, it’s easy and efficient, noninvasive
Rectal - most accurate but invasive. ~0.5 degrees above oral
tympanic - reliable and accurate but difficult to have proper technique, leading to inaccuracies ~0.8 degrees above oral
Axillary - easy and noninvasive but unreliable ~1 degree below oral
Identify the body areas used to palpate arterial pulses
Radial artery common carotid artery Popliteal artery femoral artery temporal artery facial artery brachial artery posterior tibial artey dorsalis pedis artery
Differentiate between hyperpyrexia and hyperthermia
Hyperpyrexia - extreme elevation (body temp) due to underlying disease/disorder (subarachnoid hemorrhage) - >41.5 degrees Celsius
Hyperthermia - not fever - externally induced (environmental) or secondary to drugs (anaesthetics)
Discuss the generation of fever in the hypothalamus in response to pyrogens
Temperature set point determined by the hypothalamus - fever involves changing the set point to allow for increase in body temp
Pyrogens are essentially something that can initiate fever - typically infectious organisms or their direct products (toxins)
pyrogens carried via blood and hypothalamus sits behind BBB.
- circumventricular organ system. small cluster of neurons that project trhought the BBB and have connections with the hypothalamus (these are involved in monitoring BP, GI activity, appetite and others).
- pyrogens activate specific neuronal receptors within the CVOS and prostaglandins (PGE2 through COX enzymes) are created
- PGE2 activates the febrile response in hypothalamus - initiates change in set point & activation of diverse processes to conserve heat (decreased blood flow to skin - less radiant heat)
Identify some causes of pyrexia and hypothermia.
- induced –> for surgery
- prolonged exposure to cold air and water
-response to disease
Describe the role of subcutaneous fat in relation of body temperature and describe the mechanisms that exist to conserve heat or promote heat loss.
Predict and explain the respiratory compensation mechanisms that would occur in a state of metabolic acidosis or alkalosis based on the carbonic acid equilibrium.
…in respiration section…
Predict and explain the evolution of respiratory acidosis and alkalosis and their effects on the carbonic acid equilibrium.
…in respiration section…
Describe the regulatory mechanisms that exist for the automatic control of breathing.
…in respiration section…
Describe the chemical signals that trigger changes in breathing and discuss the physiological mechanisms that exist that translate that signal into a neurological response (carotid and aortic bodies, medullary chemoreceptors)
…in respiration section…
Predict the ventilatory changes that would occur in response to excess carbon dioxide or oxygen deficiency.