Physiology Flashcards
what are the levels of organisation in physiology?
cells > tissues (a group of similar structure and specialised function) > body organs (made up of 2 or more types of primary tissue that function together to perform particular functions
what is a body system?
a group of organs that perform related functions and work together to achieve a common goal. systems work in harmony and are highly sophisticated
what must the body maintain to remain healthy?
highly regulated optimum physiological conditions
what is human physiology?
the study of normal functions of the human body and the integrative mechanisms that control them.
what is physiology essential for in a clinical setting?
understanding the body function in health and disease
understanding the patient presentations
planning and interpretation of patient investigation
planning patient management options
providing health promotion and disease prevention advice
in the cell where does a lot of physiological control occur?
the membrane
what is the change in membrane potential?
the voltage across the membrane between the inside and the outside of a cell
what is the membrane potential important for?
the functionality for nerve and muscle cells
what level do many pharmacological agents act at?
level of cell membrane to produce their therapeutic effect
what is homeostasis?
the maintenance for a stable internal environment by coordinated physiological mechanisms. several variables within the internal environment must be tightly regulated within a narrow niche
what are physiological control systems important for maintaining?
homeostasis
what are the two desired responses that physiological control systems produce?
intrinsic controls and extrinsic controls
what are intrinsic controls?
local controls that are inherent in an organ
what are extrinsic controls?
regulatory mechanisms initiated outside an organ
accomplished by nervous and endocrine systems
what is a feedforward response?
responses made in anticipation of a change
what is a feedback response?
responses made after change has been detected
what are the type of feedback systems?
positive: amplifies an initial change
negative: opposes an initial change (main type)
what is the primary type of homeostatic control mechanism?
negative feedback
what are core temperature and blood glucose regulated by?
negative feedback mechanisms
what must a negative feedback control system be able to do, to maintain homeostasis?
sense deviations (sensor) from desired range in a regulated variable that needs to be kept within a narrow range (set point) integrate information with other relevant information (control centre) make appropriate adjustment (effectors) in order to restore regulated variable to its desired range (set point)
what is blood pressure?
outwards (hydrostatic) pressure exerted by the blood on blood vessel walls. often measure the systemic arterial blood pressure and express it as systolic and diastolic blood pressures.
what is systemic systolic arterial blood pressure?
the pressure exerted by the blood on the walls of the aorta and systemic arteries when the heart contracts
what is the systemic diastolic arterial blood pressure?
pressure exerted by the blood on the walls of the aorta and systematic arteries when the heart relaxes
what is the normal systemic arterial blood pressure?
between 120/80 and 90/60, this varies between individuals
what is hypertension?
high blood pressure, clinical blood pressure of 140/90 mmHg or higher, daytime blood pressure 135/85 mmHg or higher
which way round do the systolic and diastolic numbers go?
systolic = top diastolic = bottom
what is pulse pressure?
pulse pressure is the difference between the systolic and diastolic blood pressures. usually between 30 and 50 mmHg
what is the mean arterial blood pressure (MAP)?
the average arterial blood pressure during a single cardiac cycle which involves the contraction and relaxation on the heart.
True of false, the systolic portion is twice as long as the diastolic portion
false - the diastolic portion is twice as long as the systolic
what is the simplest way to estimate MAP?
[(2x diastolic) + systolic] / 3 or DBP +1/3 of pulse pressure
what value should MAP be in order to perfuse vital organs like brain, heart and kidneys?
at least 60mmHg. must be regulated within a narrow range to ensure pressure is high enough to perfuse vital organs but not too high to damage the blood vessels or place a strain on the heart and other organs
what are baroreceptors?
mechanoreceptors which are sensitive to stretch
what are two important baroreceptors?
carotid and aortic baroreceptors