Physiology Flashcards
What are tissues?
- a group of cells with similar structure and specialised function
What are body organs?
- two or more types of primary tissues that function together to perform a specialised function
What are body systems?
- group of organs that perform related functions, to achieve a common goal
Define homeostasis
- the maintance of steady states within our bodies, by coordinated physiological mechanisms
- maintance of a constant internal environment
Describe the 3 stages that make a control center?
- sense
- integrate
- make
Explain intrinsic control
- local controls that are within the organ
Explain extrinsic control
- regulatory mechanisms initated outside an organ
- use of nervous and endocrine system
Explain feedforward control
- responses made in anticipation of a change
Explain feedback control
- responses made after a change has been detected
Explain positive feedback and an example
- amplifies an inital change
- labour contraction
Explain negative feedback and an example
- opposes inital change
- temperature regulation
Define blood pressure
- outwards hydrostatic pressure exerted by the blood on the walls of blood vessels
Systolic is when the heart _____
- contracts
Define hypertension
- clinical BP of 140/90mmHg or higher
- day time average of 135/85mmHg or higher
What is the pulse pressure? and what are its normal ranges?
- the difference between systolic and diastolic pressures
- usually between 30-50
Define mean arterial blood pressure?
- the average blood pressure during a single cardiac cycle
Diastolic is ______ as long as systolic
- twice
what is the usual value for mean arterial pressure?
- 70-105mmHg
Equations to calculate MAP
MAP = (2 x diastolic + systolic ) / 3
MAP = diastolic + 1/3 pulse pressure
MAP = CO X SVR
____mmHg is the minimum MAP needed to perfuse organs
60
What are baroreceptors?
- recognise the differences in MAP
- located in carotids and aortic arch
What happens to the firing of baroreceptors if MAP increases?
- firing increases
Define cardiac output?
- the volume of blood pumped out by each ventricle per minute
Define stroke volume?
- volume of blood pumped out of each ventricle per beat
3 ways in which MAP can be regulated?
- heart rate
- systemic vascular resistance
- stroke volume
How is systemic vascular resistance regulated?
- vascular smooth muscle
Define vasomotor tone
- when the vascualr smooth muscle is partially constricted at rest
- due to tonic discharge of sympathetic nerves
There is no significant parasympathetic innervation on arterial smooth muscle?
true/false?
- true
- only exceptions are the penis and clitoris
What are the 7 main vital signs recorded?
- pulse (60-100bmp)
- bp (<140/90mmHg - hypertensive)
- temperature (core- 37.8)
- capillary refill (>2secs)
- resp rate (12-20)
- consciousness
- oxygen saturation (<95%)
What is the core body temperature? and what are the normal range?
- the temperature deep within the body
- 37.8
Ear drum temperature range?
35.5 - 37.5
Rectal temperature range?
36.7 - 37.5
4 ways in which heat can be lost or gained in the body?
- radiation
- conduction
- convection
- evaporation
The bodys temperature is kept at a constant by _______ feedback control?
- negative
Where are the central thermoreceptors located?
- hypothalamus
- organs
Where are the peripheral thermoreceptors located?
- skin
What is the control center of body temperature?
- hypothalamus
the _____ end of the hypothalamus is activated by cold
- posterior
the ______ end of the hypothalamus is activated by warmth
- anterior
Explain how a fever is produced in response to infection
- macrophages release endogenous pyrogen chemicals in response to an infection
- these stimulate the hypothalamus to release prostaglandin
- this resets the body thermostat to a higher temperature
- imitates a cold response
what temperature represents hyperthermia?
> 40
what temperature represents hypothermia?
<35
What is the role of a membrane?
- forms a outer boundary of every cells
- selectively permeable
- controls entry of nutrients, and exit of waste products
Explain the role of phospholipids in a membrane
- hydrophilic head
- hydrophobic tail
- constantly moving –> fluid like appearance
What is the role of cholestrol in the plasma membrane?
- to provide stability
What are peripheral membrane proteins?
- loosely associated
- lie on the top of the membrane
What are integral proteins?
- closely associated
- may be transmembranal
- may act as pores, channels, pumps and enzymes
Name given to the layer formed by
glycoproteins + glycolipids?
- glycocalyx
What is used as a self-recognition marker on plasma membranes?
- carbohydrate molecules
- different cells have different carbohydrate markers
Another name for tight junctions?
- occluding junctions
Another name for desmosomes?
- anchoring junctions
Another name for gap junctions?
- communicating junctions
Role of tight junctions?
- prevents diffusion
Role of desmosomes?
- anchor cells together
Role of gap junctions?
- all the movement of ions
The plasma membrane is ____ permeable
- selectively permeable
What are the 2 main factors that influence membrane transport?
- size and solubility of ion
Explain unassisted membrane transport
- movement is either down a concentration gradient
- or along a electrical gradient
What are the 5 factors of Ficks law of diffusion?
- magnitude of concentration gradient
- surface area of membrane
- lipid solubility
- molecular weight
- diffusion distance
What does electrochemical gradient mean?
- both chemical (concentration) and electrical gradients play a role in diffusion
define osmolarity
- concentration of osmotically active ions in a solution
define tonicity
- the effect of a solution on the the cell volume
carrier mediated transport involves____ changes-
- conformational changes
What does Tm mean in relation to carrier mediated transport?
- transport maximum
- saturation kinetics
Define primary active transport
- energy is required to move an ion against its concentration gradient
Define secondary active transport
- energy isn’t used directly
- couple to an ion transport
2 different types of secondary transport?
- symport (together)
- antiport (opposite)
Energy is required for vesicular transport
- True or false?
- TRUE
2 Different types of vesicular transport?
- endocytosis
- exocytosis
Define membrane potential?
- separation of opposing charges across a membrane (Em)
The membrane of a cell is charged.
True or False?
- FALSE
- the membrane itself isnt charged
What is the concentration gradient for K+?
- outward
- Ek = -90mV
What is the concentration gradient for Na+?
- inward
- Ena= +60mV
What is the resting membrane potential? and why is it this value?
- = -70mV
- Close to Ek (=-90) but slightly more positive due to the inward leakage of Na+
How many more times permable is the membrane to K+ over Na+?
- 100 times more permeable
What directions does the Na/K+ pump work?
- 3 Na+ outward
- 2 K+ inward