SESSION 1 Flashcards
Explain the changes in the heart and lung function when exercising
Heart rate increases- pump more nutrients and oxygen to the muscles
Respiratory rate increases- increase uptake of oxygen and faster removal of carbon dioxide
A fit person has a lower pulse rate, breathing rate and lactic acid levels than an unfit person
Explain the advantages of using tympanic membrane thermometers
Tympanic thermometers are usually small hand-held devices with a probe that is inserted into the patient’s ear canal, measures the temperature of the tympanic membrane, which is a thin structure that is well perfused with blood
Advantages:
Quick and easy use so temperature can be measured more frequently
Safety- mercury spillage is not a concern
Describe the main cause of increased temperature associated with exercise
Biochemical reaction- heat produced as ATP is converted to ADP
The movement of muscle contractile proteins which would also produce heat
Why is it important for body temperature to be kept within operational limits?
Many mechanisms within the body depend on temperature, e.g. Enzymes
Hypothermia- when a person’s body temperature drops below 35C
Elderly people- can’t move to generate heat
Babies- bodies ability to regulate temperature isn’t fully developed
Hyperthermia- hyperthermia is defined as a temperature greater than 37.5–38.3 °C
The most common causes include heat stroke and adverse reactions to drugs.
Body temperature regulation- temperature too high
Hypothalamus detects change in temperature
Thermostat in the hypothalamus activates cooling mechanisms
Sweat glands activated, increasing evaporative cooling
Vasodilation: capillaries fill with blood and heat radiates from skin surface
Pilorelaxation: hairs flatten
Body temperature decreases
Body temperature regulation- temperature too low
Hypothalamus detects change
Thermostat in hypothalamus activates warming mechanisms
Shivering: rapid contraction and relaxation of skeletal muscles. Heat produced by respiration
Vasoconstriction: arteriolar get smaller to reduce blood going to the skin
Piloerection- hairs stand up
Body temperature increases
Clinical consequence of plasma potassium levels being too high and too low
Hypokalemia- too low
Symptoms: fatigue, constipation, loss of skeletal muscle, low blood pressure, excessive urination, extreme thirst
Causes: use of diuretics, kidney failure
Hyperkalemia- too high
Symptoms: slow heart rate, weakness, death
Causes: release of potassium from dying cells, kidney failure
Clinical consequence of plasma glucose levels being too high and too low
Hypoglycaemia- too low
Symptoms: sweating, hunger, nausea, confusion, seizures
Causes: liver disease, starvation, kidney failure, tumours- insulinoma
Consequence: diabetic coma, weight loss, Nerva damage, joint/ bone problems
Hyperglycaemia- too high
Symptoms: polyphasic(hunger), polydipsia(thirst), polyuria(increased urine)
Causes: diabetics, stress, beta blockers and myocardial infarction
Clinical consequence of plasma calcium levels being too high and too low
Hypocalcemia- too low
Symptoms: heart failure, muscle cramps, seizures, anxiety
Causes:hypoparathyroidism, vitamin D deficiency, kidney failure, pancreatitis, calcium channel blocker overdose
Hypercalcemia- too high
Symptoms: lack of concentration, bradycardia, muscle weakness- death
Causes: overactive parathyroid glands - lung/ breast cancer
Clinical consequence of plasma sodium levels being too high and too low
Hyponatremia- too low
Symptoms:nausea, confusion, headache, fatigue, seizures, coma
Causes:ecstasy, heart/ kidney/ liver problems, dehydration, severe vomiting/ diarrhoea
Hypernatremia- too high
Symptoms:tachycardia, mucosa, weight loss,
Hypertension- neuronal cell shrinkage (Brian injury)
Causes: decrease in total body water, same sodium levels in less water
Define entropy
Entropy means disorder
All living systems aim to minimise entropy and maximise order
Define endogenous signalling molecules
Gaseous molecules synthesised internally, in the organism
Define exogenous I signalling molecules
Natural plant based molecules
E.g. Morphine, antibiotics and aspirin
Define exogenous II signalling molecules
Synthetic man made molecules
E.g. Drugs
Define homeostasis
Maintaining the optimal internal environment for cells to function by physiological processes
Explain how control systems monitor and adjust the extracellular environment according to demand or disturbance to pertains conditions
1) stimulus produces change in variable
2) change detected by receptor
3) input information sent along afferent pathway to control centre
4) output information sent along efferent pathway to effector
5) response of effector feeds back to influence magnitude of stimulus and returns variable to homeostasis
Give examples of physiochemical parameters under homeostatic control
Temperature PH O2 CO2 H2O NA+ K+ Ca2+ Cl- Glucose
Define sensor
Detect physiological parameter
E.g. Core body temperature receptors and peripheral temperature receptors on the skin
Define set point
Compare against sensor signal to detect an error
E.g. Body temperature set point is 37 degrees
Optimum temperature for homeothermic, enzymes and proteins
Define controller
Bring system output back towards set point
E.g. Hypothalamus
Define effector
Set of components that bring about change back to optimal set point
Define the levels at which physiological control feedback loops interact
Synergistically, e.g. Temperature- skin blood supply and sweating
Antagonistically, e.g. Insulin vs glucagon
Define negative feedback
Adjusts the behaviour of the system in the opposite direction of where it is currently going
E.g. Temperature regulation- the body works to lower the temperature if there is an increase in the core temperature
Define extracellular
Situated or taking place outside the cell
Define intracellular
Located or occurring within the cell
Define endocrine
Relating to glands which secrete hormones directly into the blood
Act over long distance
Major regulation of body function via neuroendocrine system:
- digestion
- metabolism/ respiration
- growth/ development
- behaviours- sexual/ stress response
Define paracrine
Relating to a hormone which has effect only in the area surrounding the gland
Acts on shorter distances- from cell to cell
Induce changes in receptor cells
E.g. Neurotransmitters- neurone to neurone across a synapse
Define autocrine
Relating to cell- produced substance that has an effect on the cell by which it is secreted
Act over microns when released from cells
Potential cancer treatment
Overview of signalling molecule targets
Classification of drug targets:
RITE
Receptors
Ion channels
Transporter
Enzymes
Exception: chemotherapy- target is structural protein/ DNA
Overview of signalling molecule: Receptors
KING
Kinase Linked Receptors
Ion channels (Ligand gated)
Nuclear/ Intracellular
G- Protein Coupled Receptors
What is the difference between endogenous and exogenous signalling molecules binding with targets ?
Endogenous signalling molecules- optimal fit for the job
Exogenous signalling molecules - fit may be ‘sub- optimal’, possible side effects
Describe the major types of endocrine signalling molecules
Hydrophilic 1- amines
Small charged, hydrophilic
Receptors in plasma membrane
Hydrophilic 2- peptides to proteins
Short chain, insulin
Receptors in plasma membrane
Lipophilic- steroids
Derivative from cholesterol
Receptors are intracellular
Refer to comparative table on powerpoint
Describe therapeutic exogenous signalling molecules
Adrenaline- used in A & E
Insulin- controls blood sugar, diabetes
Steroids- used as an anti- inflammatory
Describe the primary signalling role of paracrine signalling molecules
Exhibitory- signal increase firing rate post- synaptically
Inhibitory- signal decrease firing rate post synaptically
Neurones can summate both kinds
Refer to comparative table for common neurotransmitter signalling functions
Local injury result in signalling response provided by paracrine signalling molecules
Local response- rapid, focused and integrated, does not involve he whole body
Define local chemical mediators
Cytokines- interleukins, chemokines, interferons and histamine
Eicosanoids- prostaglandins and leukotrienes
Others- platelet activating factor, nitric oxide and neuropeptides
Define the paracrine therapeutic exogenous signalling molecules
Hypertension- propanol antagonises adrenaline/ noradrenaline used
Parkinsonism- dopamine precursor
Depression- slow re- up take of serotonin
Epilepsy- GABA
Migrating- serotonin agonists
Inflammation- steroids blockers of inflammatory signals
Moderate pan- non steroidal anti- inflammatory black local mediator
Respiratory inflammatory responses- adrenergic agonists
Development for cancer treatment
Explain Kinase Linked Receptors
Mediate signals of wide variety of protein molecules
Act via phosphorylation of specific groups- resulting in a cascade effect
Explain ion channels ligand gate (inotropic receptors)
Many fast neurotransmitters : ACh
Modulating action potential generation in neurones and contraction in muscle
Coupled to Calcium ions
Explain nuclear/ intracellular receptors
Ligand need to be lipid soluble, e.g. Steroids
Activates/ inactivates a gene
Ligand receptor complex binds to gene transcription factor when at the nucleus
Explain G- Protein Coupled Receptors
Largest receptor group
Slow neurotransmitters; serotonin and dopamine
Three major types: Gs, Gi, Gq- activate different intracellular routes
What do ion channels do?
Selectively allow ion current to flow across the plasma membrane
Four major ion currents: Na+, K+, Ca2+, Cl-
Ion channels enable selective flow of ion current down its electrochemical gradient
Regulating ion channels
Ion channel activity can be facilitated or inhibited by phosphorylation of intracellular sites on channels via pKA, pKC and GPCR activation
Binding with exogenous channel blockers
What do transport/ carrier proteins do?
Transport of ions/ small molecules can use channels facilitated diffusion if there is gradient into/ out of the cell
Use ATP as an energy source
Used to transport across GI tract
Transport needed if highly polar or going against gradient
Give an important example of neurotransmitter re- uptake transport
Noradrenaline
Glutamate
Serotonin
Use co- transport of sodium to drive transport
What do enzymes do?
Targeting enzymes
Competitive inhibition at active binding sites with non- substrate
Increase levels of precursor substrate
