Foundation 2 Flashcards
What is the anatomical position
Head, gaze and toes directed forward
Arms adjacent to the sides with palms facing forward
Lower limbs close together with feet parallel
What is the medial plane
The vertical plane that passes directly through the body dividing it into left and right halves
What are sagittal planes
Vertical planes that pass through the body parallel to the medial plane
What are frontal planes
Planes that are vertical and split the body into anterior and posterior, right angle to the medial plane
What are transverse planes
Horizontal planes that pass through the body at right angles to the median and frontal planes
What does rostral mean
This is often used instead of anterior when describing the brain
What does medial mean
The location closer to the medial plane
What does lateral mean
This refers to something further away from the medial plane
What does superficial, intermediate and deep refer to
The position of body parts when they are underlying or overlying structures
What are bilateral structures
These are paired structures that have right and left members
What are contralateral structures
Structures found on opposite sides of the body
What is flexion
The bending or decreasing of the angle between the bones or parts of the body
What is extension
Increasing the angle between a bone or part of the body
What is dorsiflexion
Flexion at the ankle join
What is plantarflexion
This is extension of the ankle joint such as standing on your toes
What is abduction
Moving away from the medial plane such as spreading your fingers away from the middle digit
What is pronation of the forearm
Rotation of the arm so the palm faces posteriorly and the dorsum faces anteriorly
What is inversion of the sole of the foot
Moving it inwards towards the medial plane
What is elevation
The raising of parts superiorly such as shrugging
What is depression
The lowering of parts inferiorly
What is the thoracic plane
The plane at T4/5
Where is the subcostal plane
At T12 the 12th vertebrae just below the ribs
How many cervical levels are there
7
How many thoracic levels are there
12
How many lumbar levels are there
5
How many sacral levels are there
5
What is the sympathetic nervous system
This is involved in fight or flight
What is the parasympathetic nervous system
Rest and Digest
Where is the origin of the parasympathetic nervous system
Cranio-sacral origin with cranial from the brain stem
What is the make up of the sympathetic nervous system
It’s a thoraco-lumbar make up
What makes up the two-neurone model
The preganglionic and postganglionic neurone with a synapse between
How many neurones does the SNS have to go through after the spinal cord to a skeletal muscle
1
How many neurones does the ANS go through before reaching its effector
2
What ganglion is longer when comparing the sympathetic and parasympathetic nervous systems
The sympathetic contains short preganglionic neurones and long postganglionic whereas the parasympathetic is the other way round
What neurotransmitter is released by preganglionic neurones
Ach
What receptor does Ach bind to
N2
What is the most common neurotransmitter to the effector in the sympathetic nervous system
Norepinephrine
What is the most common neurotransmitter to the effector in the parasympathetic nervous system
Ach
What is the exception in which the sympathetic nervous system releases Ach
To the sweat glands
What is the anomaly with regards to the sympathetic nervous system when a postganglionic neurone is not involved
When going to the adrenal gland the preganglionic neurone directly releases Ach
What receptors bing epinephrine and norepinephrine
Adrenergic receptors
What two receptors make up cholinergic receptors
Muscarinic and nicotinic
What are metabotropic receptors
These are receptors that, upon activation, activate a G protein
What three receptor types are metabotropic
Alpha, beta (both adrenergic) and muscarinic
What are the three types of G-proteins with alpha subunits
G-protein-q
s
l
What does s and i refer to with regards to the g proteins
s is stimulatory of ATP and i is inhibitory of this
What is the role of the downstream enzyme linked with g-protein l and s
The conversion of ATP into cAMP
What is the downstream enzyme linked with g-protein q
Phospholipase C- it converts IP3 and DAG
What G protein do beta receptors release
G-protein s
What g protein do alpha 1 receptors release
G-protein q
What G protein do alpha 2 receptors release
G-protein l
What G-protein do recpetors M1, 3 and 5 release upon Ach binding and what does this produce
G-protein q to produce cAMP
What G-protein is released upon Ach binding with M2 or 4
G-protein l to inhibit cAMP production
What does binding of Ach to N1 and N2 receptors result in
Depolarisation and the opening of Na+ channels to initiate muscle contraction
What receptors have the highest affinity for binding norepinephrine?
Alpha adrenergic receptors
What receptor the highest affinity for epinephrine
Beta 2 receptors
What is the affinity for the neurotransmitters epinephrine and norepinephrine on beta 1 recpetors
Equal affinity for both
What is the epimysium
A sheet of fibrous elastic tissue surrounding a muscle
What is the myofibril
A repeated unit made up of thick and thin filaments
What is the plasma membrane in a muscle cell
Sarcolemma
What is the role of the m line
to anchor and align the thick and thin filaments
What is the I band
This contains only thin filament attached to the Z disc
Where are the thick filaments anchored to
The M line
What is the region of both thick and thin filaments
The A band
What is the region of only thick filaments
The H band
What are t-tubules
Extensions of the sarcolemma and connected to the sarcoplasmic reticulum
What connects the t-tubules with the sarcoplasmic reticulum
Terminal cristae
What three components make up the triad
Terminal cristae, sarcoplasmic reticulum and the t-tubules
What are the three different types of troponin and what do they bind
Troponin T- tropomyosin
Troponin C- Calcium
Troponin I- actin
What initiates the conformational change in troponin so that the actin filaments are exposed to the myosin heads
The binding of Ca2+ to troponin C
What does the myosin pull the actin filament towards during a power stroke
The M line
What occurs to the Z line, I band, H zone and A band during a power stroke
The Z line, I band and H zone all decrease whilst the A band remains unchanged
Where are the Ca2+ ions stored
The sarcoplasmic reticulum
What receptor does Ach bind in skeletal muscles following an influx of calcium ions in the presynaptic neurone
The N1 receptor
What does the activation of the N1 receptor in a skeletal muscle result in
The depolarisation of the membrane due to an influx of Na+ which results in the release of Ca2+ in the sarcoplasmic reticulum
What shape are smooth muscle cells
Spindle shaped with a central nucleus
What is the difference between single unit smooth muscle cells and multi unit
Single unit- when one depolarises they all do however in multi unit this doesn’t necessarily happen
What does calcium influx result in in smooth muscle cells
Ca2+ enters the cell and binds to calmodulin to form a calcium-calmodulin complex instead of binding to troponin C
How does the activation of cross bridges differ with smooth muscle in comparison to skeletal muscles
In smooth muscle the myosin heads are directly phosphorylated by the calcium-calmodulin complex
What three things are slower in smooth muscle cells in comparison to skeletal muscle
Slower Ca2+ influc
Slower cross bridge formation
Slower removal of Ca2+ so longer stages of depolarisation
What enzyme dephosphorylates the myosin heads in smooth muscle
Myosin light chain phosphotase
What hormone stimulates contraction of the uterus in pregnancy
Oxytocin
What hormone stimulates vasoconstriction and inhibits bronchioconstriction
Epinephrine
AGII only stimulates vasoconstriction
How does the Na+/K+ pump work
It actively pumps 3 Na+ out of every cell for every 2 K+ in
Why does the membrane potential in neuromuscular cells settle at -70mV even if there is still a concentration gradient
This occurs as there is still an electrochemical gradient across the membrane due to the -70mV of charge difference
As a result Na+ doesn’t move across due to it’s attraction to the -ve inside of the cell
Why does the movement of Na+ stop at +60mV despite Na+ still having a concentration gradient across the membrane
Because there is no longer an electrochemical gradient to power the movement of these ions so the movement across the membrane stops
What is the positive peak of an action potential and why does it stop there
+40mV as here voltage gated Na+ channels close rapidly to stop Na+ from entering the axon
This also opens the voltage gated K+ channels which means K+ flows out of the axon to initiate repolarisation
Why does hyperpolarisation occur
Because K+ channels close slowly so more K+ than desired is let out of the axon
Why do myelinated neurones have a faster rate of action potentials
The action potential jumps between nodes of ranvier
What is the structure of electrical synapses
These have proteins joining them called a connexon that allows neurons to flow through it and results in less delay of signal
What is the structure of chemical synapses and how does it differ to electrical ones
These contain a synaptic cleft so the neurones aren’t connected and neurotransmitters have to carry the signal across these synapses
However these synapses can be modulated whereas electrical synapses cant
What ions are at each synapse
The presynaptic neurones contain Ca2+ voltage gated channels whereas the postsynaptic neurone contains Na+ ligand gated channels
What are the two classes of neurotransmitters
Excitatory and inhibitory
What is the difference between excitatory and inhibitory neurotransmitters
Excitatory cause membrane depolarisation whereas inhibitory neurotransmitters do not cause depolarisation, instead they cause hyperpolarisation
What are the major neurotransmitters and what is their function (8)
Adrenaline (fight or flight) Noradrenaline " Dopamine (pleasure) Serotonin (dictates mood and more means happier) GABA (calming for sleep) Ach (neuromuscular junctions) Glutamate (excitatory in learning) Endorphin (euphoria transmitter after exercise)
What are ionotropic receptors coupled to
Ion channels
What type of receptors are glutamate and GABA attached to
Both metabotropic and ionotropic
What type of receptors does serotonin bind to
ionotropic receptors
What type of receptors do dopamine and norepinephrine bind to
Metabotropic
What are the five segemnts of the spinal cord
cervical, thoracic, lumbar sacral and coccygeal
How many pairs of spinal nerves are there
31
How many cranial nerves are there
12
What type of neurone is the ventral root
A motor neurone
What type of neurone is a dorsal root
Sensory
Which side of the sign is anterior, ventral or dorsal
Ventral
What kind of matter is in the spine and how is it arranged
Grey matter centrally surrounded by white matter
What is the most abundant CNS neuroglia
Astrocytes
What is the role of microglial cells
These are defensive cells in the CNS
What cells line the cerebrospinal fluid filled cavities and what type of epithelium are they
Ependymal cells
simple cuboidal epithelial cells
What is the role of oligodendrocytes in the CNS
They myelinate neurones by forming the myelin sheaths
What cells myelinate neurones in the peripheral nervous system
Schwaan cells and satellite cells
How do oligondendrocytes form myelin sheaths around Schwaan cells
They extend their plasma membrane to wrap around the neurone and they can do this on multiple different axons
What is the difference between Schwaan cells and oligodendrocytes
Schwaan cells are much closer together and can only produce one myelin sheath
What is the Therapeutic index of a drug
It is the toxic dose of a drug for 50% of the population, divided by the minimum effective dose for 50% of the population
What does a high TI suggest
That the drug has a favourable safety and efficacy profile
What can the lack of specificity of a drug result in
This can lead to unwanted side effects as it may be acting on a different area simultaneously as being effective on a target area
What is tolerance
The reduction in drug response after repeated administration of that specific drug
What is desensitisation
This is when a drug has stimulated it’s target and cannot stimulate it again rapidly after and thus doesn’t have an effect
Why may a drugs effect be reduced (5)
The receptors may undergo a conformational change that makes them harder to activate
The receptors may be internalised by the cell upon repeated activation so fewer are on the surface
The neurotransmitters or mediators may be depleted by the drugs
Usage may result in metabolic degradation
Some drugs can cause physiological adaptations such as fluid in the body
What can change the drugs effectiveness of a drug
The amount of water taken with it
The formulation and packaging of a drug
What can alter in the GI tract effectiveness in absorbing drugs
Gut motility- excessive movement leads to decreased absorption
pH- poor absorption of strong acids and bases
Interactions with food
Particle size and formulation
Gut resistant coating
What are hormones
Chemical messengers synthesised by specific tissues that are carried in the blood stream to non adjacent sites in order to elicit actions
What hormones do white blood cells produce
Cytokines that act on tissues in the immune system
What is endocrine signalling
When a cell signals to a distant cell via a hormone released into the circulatory system
What is paracrine signalling
When a cell communicates to the cell next to it
What is autocrine signalling
When a cell signals to itself
What is synaptic or neurocrine signalling
When a neuron signals to a cell using neurotransmitter
Where is the hypothalamus located
At the base of the forebrain
What is located at the inferior part of the hypothalamus
The pituitary stalk that gives rise to the pituitary gland
What are the two lobes of the pituitary gland
The anterior and posterior pituitary gland
What is the role of the posterior and anterior pituitary gland
The posterior stores hormones produced by the pituitary gland whilst the anterior actually makes some
Where are neurohormones produced by the hypothalamus secreted into
The capillary plexus in the posterior pituitary gland
Where does the anterior pituitary gland secrete its hormones
Directly into the extracellular fluid
How is the anterior pituitary gland hormone production controlled
It is instructed by the hypothalamus through hormone release
What is the role of TRH
It stimulates the release of thyroid stimulating hormone and prolactin
What is the role of GnRH
it stimulates FSH and LH production
What is the role of CRH
It stimulates adrenocorticopic hormone (ACTH) and this is essential for adrenal gland functioning
What is the role of GHRH (growth hormone regulating hormone)
It stimulates growth hormone release
What is the role of PRF (prolactin release factor)
stimulates the release of prolactin
What inhibits prolactin release
Dopamine
What does growth hormone do
It stimulates growth and targets the liver
What does thyroid stimulating hormone do
It targets the thyroid glands to release thyroid hormone that regulates the bodys metabolic rate
What is the role of prolactin
It acts on the mammary glands and reproductive organs and stimulates milk production
What does ACTH do
It targets the adrenal cortex to release cortisol
What and how does excess growth hormone result in
Acromegaly which occurs when more growth hormone is produced despite the growth plates being closed
Gigantsim occurs when there is excess before the plates close
What can growth hormone deficiency cause
Dwarfism
What does a lack of ADH result in
Cranial diabetes insipidus that results in thirst and dilute urine production
What is Kallmann syndrome
The lack of GnRH which reduces LH and FSH secretion
What occurs when the brain feels physical or emotional stress
The brain releases corticotropin-releasing hormone that stimulates the pituitary gland to release ACTH
This stimulates the adrenal glands to release cortisol
What does nervous stimulation of the adrenal glands result in
Release of adrenaline
Where are the adrenal glands located
Above the kidneys
What are the three layers in the cortex of an adrenal gland from superficial to deep and what do they secrete
Zona glomerulosa- mineralocorticoids
Zona fasciculata- secretes glucocorticoids involved in stress responses
Zona reticularis- secretes an androgen precursor DHEA and glucocorticoids
What can excess cortisol lead to
Cushing’s syndrome
What results in too little aldosterone and cortisol
Addison’s disease due to adrenal cortex insufficiency and this results in degradation of the adrenal glands
What are examples of positive feedback
Oxytocin secretion during childbirth and oestrogen secretion in the menstrual cycle before ovulation
What are steroid hormones synthesised from
cholesterol
How can steroid hormones pass through the plasma membrane
They’re lipophilic so can diffuse through the plasma membrane
How do steroid hormones travel in the bloodstream
They travel bound to plasma proteins as they’re hydrophobic
Where are non-steroid hormones stored
secretory vesicles in cells
What happens to the Cell surface receptor when a hormone binds to it
They undergo a conformational change on the intracellular domain
How do steroid hormones interact with target cells
They bind to intracellular receptors and then cause a conformational change and enter the nucleus, binding to specific sections of DNA called hormone response elements to inhibit or stimulate it
What is the first step of cell surface receptors upon activation
They phosphorylate proteins
What does a G protein do upon activation
It gains GTP after losing GDP and breaks down this GTP into GDP
How do tyrosine kinase receptors work
ATP is hydrolysed into ADP and the phosphate group phosphorylates tyrosine alongside tyrosine kinase
This triggers the release of relay proteins
What effector protein converts ATP into cyclic AMP which acts as a secondary messenger
Adenylate cyclase
What is PIP2 broken down into to form a secondary messenger
IP3
What is the role of IP3
It binds to the ER to open ligand gated Ca2+ channels that activates multiple cellular responses
What is a drug
A chemical, other than an essential nutrient, which when administered, produces a biological effect
What is therapeutics in medicine
The area concerned with the treatment of disease
What is pharmacokinetics
The measurement and formal interpretation of changes with time of drug concentrations in one or more different regions of the body
What are the four phases of pharmacokinetics
Absorption
Distribution
Metabolism
Excretion
What are the 5 different routes of drug administration
Oral or rectal, precutaneous (skin), intravenous, intramuscular and inhalation
Why might some drugs be taken simultaneously with other drugs despite not having a target organ
They may increase the absorption of the other drug that has a specific function
What molecules move through the membranes most effectively
small hydrophobic molecules
How rapidly do small uncharged polar molecules move through the plasma membrane
Quite quickly although the polar nature provides a slight barrier
How fast do large uncharged molecules diffuse through the membrane
Quite slowly due to their size
How quickly to ions diffuse through the plasma membrane
They can’t
What is the pKa of a drug
The value of the pH at which the drug exists in a 50% ionised state
What is the volume of distribution
The volume of litres that the drug distributes in comparison to the entire body water volume over a given time
What is Kel
This is the elimination rate constant of a drug
What effects the rate of distribution of a drug
Membrane permeability and blood perfusion
What effects the distribution of a drug
Lipid solubility
plasma protein binding and tissue bending
How is there a constant elimination of drugs from cells
As the drug is eliminated from the plasma this sets up a concentration gradient for the drug to move out of cells and into the plasma
If a drug is a high plasma bound protein drug will this have a slower or faster effect
Slower
What effects can the liver and gut have on drug action
They may reduce drug action as they absorb the drug before it reaches its target
What is bioavailability
The proportion of drug dose which appears in the systemic circulation following administration
Why does IV have a bioavailability of 100
because it bypasses the gut and liver
Why are oral drugs bioavailability almost always below 100%
Because they have to bypass the liver and GI tract
What affects rectal bioavailability
The interference with the GI tract
However some drugs can be absorbed directly in the rectal area
What is the main family of enzymes, commonly found in the liver and GI tract, that are frequently involved in drug metabolism
Cytochrome P450 enzymes
What is phase 1 of drug metabolism
The chemical modification of a drug to produce a marked change in biological effect
What is phase 2 of drug metabolism
Metabolic reactions that add groups to the drug in order to prepare it for secretion
What is pharmacodynamics
What the drug does to the body and refers to the events after the drug interacts with it’s receptor
What is a ligand gated ion channel with regards to drugs
When a drug binds this may open or close this channel
This may change the charge in a cell rapidly
What are kinase linked receptors and what can they do
These are linked to phosphorylation pathways to affect things such as gene transcription or protein synthesis
What is an agonist
This is a ligand that binds to a receptor to cause a biological cellular response
What is the affinity of a drug
How easily the drug will bind with its receptor to form an agonist-receptor complex
What is the EC50 concentration
The concentration of the drug that requires 50% effect and defines the affinity of the drug to its receptor
What is the efficacy of an agonist
The ability of a drug to elicit a response upon binding to its receptor
What is the efficacy of a full agonist
1
What is an antagonist
This binds to a receptor but doesn’t activate it
Do antagonists have affinity?
Yes
What is the efficacy of antagonists
0 as it elicits no response upon binding to a receptor, it is merely competitive
Do reversible antagonists bind to the same or different sites on a receptor as the agonist
The same
How can you overcome reversible antagonists
Increasing the concentration of the agonist
What is lowered in the presence of a competitive antagonist
The EC50
Is the binding of a non-competitive antagonist reversible or irreversible
irreversible
What changes in the presence of a non competitive antagonise, the efficacy or the EC50
The efficacy
