Glands Flashcards
What is a gland?
an epithelial cell or an aggregate of epithelial cells that are specialised for the secretion of a substance
Define secretion
the production and release of materials by a cellular aggregate of cells
What is an exocrine gland?
ducted
enzymes and lubricants
example salivary gland
What is the hybrid cell that is seen in some exocrine ducts? What are their role?
myoepithelial cells
help eject the secretion from the duct
What is an endocrine cell?
ductless release into bloodstream
hormones
example thyroid
What are the shared steps of gland development generated in utero? What the happens in endocrine and exocrine cells?
growth factors cause proliferation and extracellular protein degradation by enzymes creates space
epithelial cell invade.
Endocrine- angiotensin to allow formation of bv’s and apoptosis of link to mother cell.
Exocrine- central cells die off to create duct
What is merocrine secretion?
fusion of vesicles with apical membrane
exocytosis
regulated and constitutive
insulin from beta cells
What is apocrine secretion?
partial loss of the cytoplasm
lactation mammary glands
What is holocrine secretion?
complete loss of cytoplasm
sebaceous glands
What is cytocrine secretion?
cells released as secretion
sperm
What is glycosylation?
covalent attachment of sugars by enzyme to protein and lipids to form glycoproteins and glycolipids
Define exocytosis
vesicles fuse to membrane and secretion released outside cell
define endocytosis
engulfing of molecules inside the cell via vesicle formation
define phagocytosis
cells envelop/ engulf other cells and particles
define pinocytosis
process in which liquid droplets are ingested by cells
Name the 4 types of transepithelial transport
paracellular
transcellular
carrier proteins
receptors–> endocytosis –> exocytosis
Name the 4 types of glandular control with examples
humoral- parathyroid in response to decrease Ca
neural- catcholamines form adrenal medulla
hormonal- hypothalamus–> anterior pituitary–> another endocrine gland
Name the hormones produced by the anterior pituitary
TSH ACTH FSH LH GH prolactin melanocyte-stimulating hormone
Name the hormones produced by the posterior pituitary
ADH (vasopressin)
oxytocin
Name the hormones produced by the thyroid gland
T3 and T4
calcitonin
Name the hormone produced by the parathyroid gland
parathyroid hormone
Name the hormones produced by the adrenal glands
catecholamines
corticosteroids
aldosterone
Name the hormones secreted by the pancreas
glucagon
insulin
somastatin
Name 4 types of hormone
peptide
steroid
amino acid derives- catecholamines and thyroid H’s
What gestational weeks to gland develop?
5-16
Where does the pituitary develop from?
neurohypophyseal bud and hypophyseal pouch
Where does the thyroid develop from?
floor of pharynx and 2nd pharyngeal pouch
Where does the parathyroid develop from?
3rd/4th pharyngeal pouches
where does the pancreas develop from?
fore gut
where does the adrenal glands develop from?
intermediate mesoderm and neural crest
How many hormones does the hypothalamus produce that act on the anterior pituitary?
6
What are the two portal systems in the body?
hypothalamus hypophyseal portal system
hepatic portal system
What defines a portal system?
capillaries to portal vessels to capillaries then to veins and back to heart
What is the skin that joins the two lobes of the thyroid?
isthmus
Name a hypothyroid condition
hashimoto’s
name a hyperthyroid condition
graves
What do parafollicular cells produce ?
calcitonin
What are the main effects of calcitonin?
decrease Ca
inhibit osteoclasts
prevent reabsorption of ca and phosphate in kidney
What does the parathyroid hormone do?
increase Ca
cause bone to release calcium and increase it absorption in the GI tract
What shape is the right adrenal gland?
pyramid
What shape is the left adrenal gland?
crescent moon shape
What. cells in the medulla are connected to the presynaptic sympathetic nerves?
chromaffin cells
What hormones are released by the adrenal medulla
adrenaline
noradrenaline
What is produced by the zone glomeruloas of the cortex?
aldosterone
What is produced by the zone fasciculata of the cortex?
glucocorticoids
What is produced by the zone reticularis of the cortex?
androgen precursors
What is the stress response?
maintenance of homeostasis in the present of a aversive stimulus that requires the activation of the endocrine, nervous and immune systems
Where does the head of the pancreas sit?
curve of duodenum
Where is the pancreas found?
behind stomach, left hand side
What enzymes are produced by the exocrine region of the pancreas?
chymotrypsin trypsin amylase lipase ribonuclease deoxyribonuclease elastase gelatinase
What type of epithelial cells line the intercalated ducts
simple columnar epithelium
What is the endocrine region of the pancreas called?
islets of langerhans
what do the alpha cells of the pancreas produce?
glucagon
what do the beta cells of the pancreas produce?
insulin
what to the delta cells of the pancreas produce?
Somastatin
Secretion from parotoid gland?
predominantly serous
Where is parotoid gland located?
below and infront of the ear
What are the two parts of the submandibular gland and what do they secrete?
superficial- mucous
deep- serous
How does parasympathetic ns affect salivary secretion?
lots watery saliva
How does sympathetic ns affect salivary secretion?
small amount of thick secretion
lots of mucus
Where is liver located?
right hand side under ribcage
What are the blood supplied to the liver?
hepatic artery
hepatic portal system
What vessels are in the portal triad?
bile duct, hepatic artery, hepatic portal vein
What type of capillaries line the vessel in the liver?
sinusoids
also found in the spleen
What do zone 1 hepatocytes do?
gluconeogensis
beta oxidation
cholestrol synthesis
What do zone 2 hepatocytes do?
glycolysis, lipogeneis and cytochrom P450
What do zone 3 hepatocytes do?
minimal metabolic function
where drug toxicity occurs
List 4 main hepatocyte functions
protein synthesis and storage
carb metabolism and storage
lipid metabolism
detoxification
What are kupffer cells? What roles do they carry out?
specialist macrophages part of sinusoidal lining
remove bacteria
remove damage erthyrocytes (spleenectomy especially)
migrate sites of inflammation
What is the role of ito/ stellate cells?
contain vitamin A in healthy liver
damaged liver- differentiate to myofibroblasts causing fibrosis
What isa the role of the dendritic cell?
function unknown possibly antigen presenting and recruitment of other immune cells
