Physiology and Anatomy Flashcards
4 chemical types of hormones
modified amino acids
steroid
peptide
protein
example of a protein hormone
insulin
modified amino acid acids eg from __+__
examples __+__
tyrosine and tyramine
adrenaline, T3 and T4
examples of steroid hormones
cortisol, progesterone, testosterone
examples of peptide hormones
ACTH oxytocin ADH
6 main hormones from anterior pituitary
It releases ___ chemical type hormones
ACTH, GH, FSH, LH, prolactin, TSH
peptide/protein
intermediate pituitary hormone
MSH
posterior pituitary hormones
ADH/vasopressin
oxytocin
pineal gland hormone
and its target
melatonin
hypothalamus
Zollinger Ellison syndrome is a tumour of the ___ that releases ___
pancreas/duodenum
gastrin
definition of autocrine
acts on the same cell
definition of paracrine
acts on other cells within that organ/tissue
definition of endocrine
enters circulation to act on distant cells
hormones act at __ concns over a ___ distance with ___ receptors and __ potency
low concns
large distance
specific receptors
high potency
3 hormones involved in homeostasis short term during exercise and their function
glucagon - gluconeogenesis and glucose release
cortisol - enhance metabolic use of glucose
adrenaline - prevent hypoK+
4 hormones involved in long term effect of exercise for normal growth
GH
insulin
IGF-1
sex hormones
insulin has antagonistic actions to __+__
adrenaline and glucagon
amine hormones: ___ converted to adrenaline it is then ___ and then released in response to ___ = ___ - is highly hydrophilic and so travels ___ in plasma
tyrosine stored pre-synthed in vesicles Ca2+ in cell exocytosis free in plasma
peptide and protein hormones:
precursor (synthed at __) >____>hormone>____>___dependent exocytosis>highly hydrophilic so travels ___
rER proteolytic steps by convertases stored pre-synthed in vesicles Ca2+ free in plasma
steroid hormones:
__+__ stimulated > __ uptake > converted into ___ (rate limiting step) > steroid hormone which is ___ and released>is ___ and so 90% travels bound in blood
intracellular ligand and receptor cholesterol uptake pregnenolone not stored hydrophobic
carrier proteins provide a ___ for hormones and increase ___ and so maintains a ___ concn
reservoir
t1/2
relatively constant
3 specific carrier proteins
CBG - binds cortisol
TBG - binds T4
SSBG - bind sex steroid hormones
general carrier proteins (2)
albumin (steroids and thyroxine)
transthyretin (thyroxine and some steroids)
5 factors that the control of hormone levels depend on
rate of secretion negative feedback neuroendocrine circadian rhythm rate of elimination
t1/2 of amine, peptide/protein and steroid+thyroid hormones
amine - seconds
p+p = minutes
s+t = hours-days (due to carrier protein binding)
GPCR are the receptors for __+___ hormones eg.
amines and some peptides
adrenaline, glucagon, CRH,ATII, GRH, TRH, malatonin
ATII/GRH/TRH to GPCR => __>__/__
Gq
IP3
PKC
adrenaline, glucagon CRH to GPCR =>__>__>___>phosporylation
Gs
increase cAMP
PKA
melatonin to GPCR => __>__>__
Gi
decrease cAMP
decrease PKA
type of receptor for protein and peptide hormones
receptor kinase on cell surface
type of receptor that is for insulin
receptor kinase on cell surface
insulin binds to ___ (receptor) to cause ____ which recruits ___ notably ___
receptor kinase
autophosphorylation of intracellular tyrosine residues
adapter proteins - ISR1
Class 1 nuclear receptors are activated by __ hormones
in inactive form are found in ___ bound to __
then bound to and move to __ to ___ genes
steroid cytoplasm inhibitory HSPs nucleus transactivate/repress genes
Class 2 nuclear receptors activated by __
are found in the __ always
lipids
nucleus
Hybrid nuclear receptors are activated by ___
T3 and others
exocrine pancreas is made of __ cells
acinar
pancreatic islet cells and their % they contribute to its composition
alpha (10-20%)
beta (60-80%)
𝛿 (5%)
PP (<1%)
glucagon is produced by __ cells in the __
alpha
pancreas
somatostatin is produced by __ cells in the pancreas
𝛿
Insulin production:
synthed in __ of beta cells as a ____>cleaved to leave signal peptide + __>insulin + ___ (used to measure insulin release)
rER
larger single chain preproinsulin
proinsulin
C peptide
biochemistry of insulin =
2 polypeptide chains linked by disulfide bonds
glucose enters beta cells by ___ >___ phosphorylates > increase __>increase __concn> inhibits ___> increase intracellular __ depolarises cell membrane> __ open > increase __ > __ fuse with cell membrane and insulin is released
GLUT2 glucokinase metabolism of glucose ATP KATP channel K+ voltage-gated Ca2+ channels intracelular Ca2+ vesicles
release of insulin is ___ as 5% are in ____ then the rest are in ____ which need to be acted upon before release
biphasic
RRP (readily releasable pool)
reserve pool
2 proteins in KATP channels
is a __ structured channel
inward rectifier - KIR6 - pore subunit
sulfonylurea receptor - SUR1 - regulatory subunit
octomeric
3 things that regulate KATP channels
___ inhibits by binding to __
directly inhibited by ___ on ___
stimulated extracellularly by ___ on ___ to inhibit insulin release
intracellular ATP KIR6
sulfonylurea drugs SUR1
diazoxide on SUR1
neonatal diabetes is caused by __ mutation causing __ of KATP channels
Rx =
KIR6.2
overactivity
sulfonylureas
inhibiting mutations on __/__ can cause congenital hyperinsulinaemia
Rx =
SUR1/KIR6.2
diazoxide
diencephalon = __+__
thalamus and hypothalamus
infundibulum connects __ to __
hypothalamus to pituitary
pituitary gland lies in the ___ in the __ in the ___ bone
pituitary fossa
sella turcica
sphenoid
temporal side of vision is seen on the ___ retina
nasal
nasal side of vision is seen on the ___ retina
temporal
inbetween retina and optic chiasm in visual pathway =
optic canal
between optic chiasm and thalamus synapse in the visual pathway
optic tract
pituitary lies __ to the optic chiasm
inferior
the ___ optic canals cross sides at the optic chiasm
nasal (from temporal light rays ->nasal retina)
nasal light rays > ___ retina > ___ optic canal and tract
temporal
ipsilateral
temporal light rays > ___ retina > ___optic canal > ___ > ___ optic tract
nasal
ipsilateral
optic chiasm
contralateral
pituitary tumour can cause this visual defect because it compresses the optic chiasm
bitemporal hemianopia
most common Sx approach to the pituitary
transsphenoidal (via nasal cavities and sphenoid sinus - surgically # the nasal septum)
nasal conchae bones =
sup and middle from ethmoid
inferior = its own bone
roof of nasal cavity made from
cribriform plate of ethmoid bone
superior part of nasal septum is made from
perpendicular plate of ethmoid bone
inferior nasal septum is made from
vomer
4 paranasal sinuses=
ethmoid air cells
sphenoid
maxillary
frontal
paranasal sinuses drain through __ to __
ostia
nasal cavities
adherent to the internal aspects of all the cranial vault bones
dura mater
pituitary lies inferior to ___ (dura mater)
diaphragm sella
tentorium cerebelli =
dura mater over the cerebellum with central gap for the brainstem
below dura mater in middle cranial fossa that are susceptible to damage by a pituitary tumour =
CN II, III IV, V, VI
dural venous sinuses
dural venous sinuses =
venous channels in dura mater that drain most of the blood from the cranial cavity to the internal jugular veins
___ pass through the cavernous sinuses
internal carotid arteries
cavernous sinuses lie ___ to pituitary
lateral (on both sides
intercavernous sinus connects ___ lies ___ to pituitary
R+L cavernous sinuses
anterior
8 structures at risk in pituitary Sx
CN III CN IV CN V CN VI optic chiasm cavernous sinus ICA dura mater
functions of CNIII (3)
motor to 4/6 occular muscles
constrictor pupillae
elevates upper eyelid
damage to CN III causes
eye movement problems
dilated pupil
CN IV function
moves eye up and down
CNV functions (2)
facial sensory
muscles of mastication motor
CNVI function
lateral rectus motor supply - abducts eyeball
Thyroid lobes attach to __+__+__
trachea
thyroid cartilage
cricoid cartilage
isthmus of thyroid lies anterior to __+__ tracheal cartilages
2nd and 3rd
pyramidal lobe of thyroid is present in __% of population
usually originates from the __ lobe
most attach to __ but may extend to __
28-55%
Left
thyroid cartilage
hyoid bone
embryology - thyroid starts as an ___ at the junction between __+__ (___ in adults)
epithelial proliferation
ant and post tongue (foramen caecum)
embryology:
thyroid migrates inferiorly but still attached to tongue by ___
thyroglossal duct
thyroid reaches its final destination by ___ gestation
wk7
__/___ can be found anywhere along the migratory pathway of the thyroid
thyroglossal duct cysts
ectopic thyroid tissue
platysma is supplied by __ as it is a ___
CNVII
muscle of facial expression
thyroid lies at ___ with ___ in superficial fascia anteriorly
C7
platysma muscle
prevertebral (deep) fascia is located __ to thyroid and contains ___+__
posteriorly
cervical vertebrae
postural neck muscles
investing (deep) fascia encloses ___ +__+__
all other neck fascial compartments
sternocleidomastoid
trapezius
carotid sheaths contents
IJV
CNX
deep cervical lymph nodes
common>ICA
pretracheal (deep)fascia encloses ++++_
strap muscles thyroid trachea oesophagus recurrent laryngeal nerve
___ lies between pretracheal and prevertebral fascia
retropharyngeal space
attachments (3) of the sternocleidomastoid
manubrium
medial clavicle
mastoid process of temporal bone
___ nerve supply to sternocleidomastoid and trapezius it lies ___
CNXI
in between them
___ lies anterior to sternocleidomastoid and drains to the EJV
anterior jugular vein
__+__ lie posterior to sternocleidomastoid
trapezius
External jugular vein
EJV drains to the ___
subclavian vein
descending part of trapezius attaches to
occipital bone
spine of scapula
lateral clavicle
superior thyroid artery is a branch from _
ECA
inferior thyroid arteries are branches from __
subclavian arteries
superior middle and inferior thyroid veins drain to __
IJV
lymphatics of the thyroid (4)
superior and inferior deep cervical nodes
pretracheal
paratracheal
CNX connects with ___ at brain >___>carotid sheath
medulla oblongata
jugular foramen
somatic branches of CNX in neck =
superior and right recurrent laryngeal nerve
the route of the Right recurrent laryngeal n. in the chest
lateral right aspect of trachea
posterior to right lung root
onto oesophagus
right laryngeal recurs under the ___
left under the ___
both pass __ to the thyroid
right = subclavian artery
left = aortic arch
posterior
contents of carotid sheath lateral to medial
IJV > CNX>common carotid
3 strap muscles =
omohyoid
sternohyoid
thyrohyoid
attaches the intermediate tendon of omohyoid to the clavicle
fascial sling
collar incision goes through the __+__
skin
platysma
unilateral recurrent laryngeal nerve injury results in:
bilateral results in :
uni = hoarse/weak voice and weak cough bi = aphonia and can't close rima glottis to produce a cough
__+__ have cytokine receptors linked to tyrosine kinase activity
prolactin and GH
accuracy of measuring levels of hormones depends on (6)
main = rate of secretion pattern of secretion carrier proteins interfering agents t1/2 absolute concns
___ is measured to assess GH levels because GH -> __ = ___ formed
IGF-1
liver
IGF-1
time to measure levels of testosterone as this is when they are highest
9am
prolactin secretion is under tonic inhibition by
hypothalamic dopamine
physiological causes (3) of hyperprolactinaemia
pregnancy
lactation
nipple stimulation
pathological causes of hyperprolactinaemia (7)
prolactinomas dopamine antagonists CKD hypophysitis ovarian dermoids hypernephroma bronchogenic carcinoma
95% of CAH is caused by deficiencies in __/___
21-hydroxylase
CYP21A2
CAH hormone effects
increased aldosterone and cortisol
decerased androgens
if suspect hormone excess = ___test
if deficiency = ___ test
excess = suppression deficiency = stimulation
stimulation test for cortisol deficiency =
synacthen
suppression test for cortisol excess =
dexamethasone
70% of Cushings is caused by
tumour from ant pit corticotroph cells - Pituitary Cushing’s
if suspect Cushings Ix = screening ___ => formal diagnostic test ____
1mg overnight dexamethasone suppression test
low dose dexamethasone suppression test
If ACTH decreased in dexamethasone suppression test =
likely an adrenal cause
If ACTH increased in dexamethasone suppression test =
still need to distinguish if is Cushing’s syndrome or ectopic ACTH
If increase in cortisol and ACTH on CRH test = ___ source => ___ (Ix)
pituitary
MRI pituitary
Ix used to lateralise a pituitary tumour pre Sx
inferior petrosal sinus sampling
