SUGER Flashcards
2 fundamental layers of the skin
dermis
epidermis
epithelium of the epidermis
stratified squamous keratinising epithelium
4 main layers of the epidermis
germinative layer
spinous/prickle cell layer
granular layer
dead keratinised squames
what granules does the granular layer of the epidermis contain?
keratohyaline granules (the precursors of keratin)
which is the thickest layer of the epidermis?
spinous layer
2 main layers of the dermis
a layer rich in collagen fibres close to the epidermis
a deeper fatty layer
which layer of the skin contains the roots of hairs?
dermis
The majority of the cells of the epidermis are…
keratinocytes
keratinocytes are derived from stem cells within the ——– layer of the epidermis
germinal
what cells are present in the epidermis, other that keratinocytes?
melanocytes
which part of the embryo are melanocytes derived from?
neural crest
what do melanocytes do?
produce melanin pigment granules
skin colour is proportional to the amount of melanin stored in the…
keratinocytes
spinous layer cells are joined together by…
desmosomes
what are Langerhan’s cells?
antigen detecting cells, part of the immune system of the skin
what do Merkel cells do?
convey the sensation of fine touch by forming synapses with nerve fibres in the dermis
name the autonomically innervated smooth muscle that causes hair to stand on end
erector pili muscle
which glands lubricate hair follicles?
sebaceous glands
what are finger and toenails composed of?
compacted keratin
what type of epithelial cells surround the tightly coiled secretory tubule of sweat glands
myoepithelial cells
name the mucous membrane that lines the inside of the eyelid and the front of the eye
conjunctiva
conjunctiva that lines the inside of the eyelid comprises of what type of epithelium?
stratified columnar epithelium composed of just 2 layers of cells
name the largest gland in the eyelid, that reduces evaporation from the cornea of the eye
Meibomian gland
what do endocrine glands do?
secrete hormones into the blood stream for circulation around the body
4 classes of hormones
amino acid derivatives
steroids
small peptides
proteins
what type of hormone is adrenaline?
amino acid derivative
what type of hormone is testosterone?
steroid
what type of hormone is insulin?
protein
what type of hormone is vasopressin?
small peptide
what is the embryonic origin of the posterior pituitary?
neuronal origin - it is a down-growth of the brain
the posterior pituitary is attached by the pituitary stalk to the…
median eminence of the mid-brain, in the floor of the 3rd ventricle
The posterior pituitary contains nerve endings. Where are the cell bodies of these axons located?
in the supra-optic and para-ventricular nuclei of the hypothalamus
what do the nerve endings in the posterior pituitary secrete into the bloodstream?
vasopressin (ADH)
oxytocin
what is the embryological origin of the anterior pituitary?
it is of epithelial origin and is derived from the roof of the primitive gut tube
which part of the pituitary gland surrounds the pituitary stalk?
anterior pituitary
3 hormones secreted by the anterior pituitary
growth hormone (GH)
follicle stimulating hormone (FSH)
thyroid stimulating hormone (TSH)
Meaning of adenohypophysis
another name for the anterior pituitary (of epithelial origin)
Meaning of neurohypophysis
another name for the posterior pituitary (of neuronal origin)
what regulates the release of trophic hormones produced by the anterior pituitary ?
releasing or inhibitory factors produced by neurones of the hypothalamus
how far do the neurones of the hypothalamus project?
as far as the median eminence
how do releasing or inhibitory factors produced by neurones of the hypothalamus reach the anterior pituitary?
- neurones release their secretions at the median eminence
2. secretions taken up into the capillaries of the pituitary portal system & carried to the anterior lobe
what is a portal system?
one that starts and ends as capillaries
5 mains classes of cells in the anterior pituitary
gonadotrophs somatotrophs lactotrophs corticotrophs thyrotrophs
name the upward extension of the anterior pituitary that surrounds the pituitary stalk
tuberal lobe
tuberal lobe contains mostly which type of cell?
gonadotrophic
name the small gland that is a backward projection from the 3rd ventricle below the corpus callosum, and is covered by the meninges
pineal gland
what sort of innovation does the pineal gland receive?
from the autonomic NS
describe the location of the thyroid gland in the neck
between the level of the thyroid cartilage (superiorly) and the 4th tracheal ring (inferiorly)
The thyroid gland synthesizes, stores and secretes which two hormones?
thyroxine and calcitonin
where are the 4 parathyroid glands located in relation to the thyroid gland?
embedded in the posterior border of each lobe
C cells of the thyroid gland produce what?
calcitonin
calcitonin is antagonistic to which other hormone?
parathyroid hormone
parathyroid gland often contains a mixture of which 2 cell types?
fat cells (apidocytes) and secretory cells
main secretory cell of the parathyroid gland
chief cell
Pancreatic islets of Langerhans are most numerous in which part of the gland?
the tail
Pancreatic islets of Langerhans constitute what % of the mass of the gland?
about 5%
Pancreatic islets of Langerhans contain which 4 secretory cells types?
- insulin secreting beta cells
- glucagon secreting alpha cells
- somatostatin secreting delta cells
- pancreatic polypeptide secreting cells
do the suprarenal glands lie inside or outside the capsule of the kidney?
enclosed inside
outer cortex of the suprarenal glands produces what?
steroid hormones
the inner medulla of the suprarenal glands produces what?
adrenaline and noradrenaline
the central vein of the suprarenal glands carries hormones to which veins?
renal veins
or directly into inf. vena cava
3 zones of the suprarenal cortex
glomerular (outer)
fascicular
reticular (inner)
what hormone does the narrow outer glomerular zone of the adrenal cortex produce?
aldosterone
what hormone does the thick intermediate fascicular zone of the adrenal cortex produce?
cortisol
what hormones does the of the inner reticular zone of the adrenal cortex produce?
sex steroid hormones
where are adrenaline and noradrenaline stored until required?
in neurosecretory granules in the cytoplasm of the cells
anterior pituitary produces what type of hormones?
peptide based
the anterior pituitary receives its blood supply from a portal circulation which starts where?
the hypothalamus
where does the thyroid originate from embryonically?
the floor of the mouth
C cells produce calcitonin when blood calcium concentration…
rises
which part of the pancreas secretes into the duodenum?
exocrine
the islets of Langerhans secrete hormones into…
the hepatic portal circulation
purpose of the hepatic portal system
responsible for directing blood from parts of the gastrointestinal tract to the liver
alpha cells in the islets of Langerhans produce what?
glucagon
what does glucagon do?
causes hepatocytes to release glucose
beta cells in the islets of Langerhans produce what?
insulin
the adrenal cortex uses what to synthesise hormones?
cholesterol
the adrenal medulla is supplied predominantly by which part of the N S?
sympathetic
the islets of Langerhans arise embryonically from the…
primitive gut tube
the parathyroid glands arise embryonically from the…
primitive gut tube
the thyroid gland arises embryonically from the…
primitive gut tube
