Exocrine and Endocrine Glands Flashcards
what is a gland?
a functional unit of cells that work together to create and release product
which type of gland secretes directly into the bloodstream?
endocrine glands
which type of gland secretes into a ductal system?
exocrine
is the hypothalamus an exocrine gland?
no
is the pancreas an endocrine gland?
yes
are the thyroid and parathyroid glands exocrine or endocrine?
endocrine
what is the function of the thyroid?
produce thyroid hormone (thyroxine, triiodothyronine)
produce calcitonin
what does the pancreas secrete?
insulin and glucagon
what is the control centre of the endocrine system that controls all the hormones of the body?
the pituitary gland
what is the anterior pituitary known as?
adenohypophysis
what is the posterior pituitary known as?
neurohypophysis
what is the Adenohypohysis made of?
- Pars distalis
- Pars tuberalis
- Pars intermedia
what is the neurohypophysis made of?
- Pars nervosa
- Median emminence
- Infundibular stalk
what controls the secretion of hormones from the anterior pituitary?
regulating hormones produced by the hypothalamic neuron
what are paracrine hormones?
hormones that effect nearby cells
what accounts for 75% of hypophyseal tissue?
pars distalis
what glandular cells are found in the pars distalis?
basophils, acidophils, chromophobes
what are all the hormones of the adenohypophysis made of?
protein or glycoprotein
what is the most dominant cell type in the pars distalis?
acidophils
what are the subtypes of acidophils and what do they secrete?
somatotrophs secrete growth hormone
mammotrophs secrete prolactin
what are the subtypes of basophils and what do they secrete?
Thyrotrophs produce thyroid stimulating hormone
Gonadotrophs produce FSH and LH
Corticotrophs (or adrenocorticolipotrophs) secrete adrenocorticotropic hormone (ACTH or corticotropin) and lipotropin (LPH).
what does LH stimulate?
production of testosterone by Leydig cells in males in addition to late follicular maturation, oestrogen secretion and formation of corpus luteum in females
what do chromophobe cells represent?
acidophil and basophilic cells in a dormant or recently degranulated stage, are weakly stained
what does the neurohypophysis consist of?
unmyelinated nerve fibres derived from neurosecretory cells of the supraoptic and paraventricular hypothalamic nuclei and
pituicytes
what are dilations of hypothalamic nerve fibres called?
herring bodies
what hormones are secreted by the neurohypophysis?
- Release-inhibiting and releasing factors, which regulate the activity of the adenohypophysis
- oxytocin
- antidiuretic hormone (ADH or vasopressin)
what does oxytocin stimulate?
the contraction of smooth muscle cell in the uterus and participates in the milk ejection reflex
what does adh facillitate?
the concentration of urine in the kidneys and, thereby, the retention of water
what surrounds the pineal body?
pia mater, which functions as its capsule and which sends connective tissue septa into the pineal body, subdividing it into lobules
what are the cells of the pineal body?
pinealocytes and astrocytes
what does the pineal body secrete?
melatonin
what does the thyroid consist of?
rounded cysts, follicles, which are separated by scant interfollicular connective tissue
what is the secretory product of the follicular cell of the thyroid?
colloid, which contain thyroxine and thriiodothyronine
does the thyroid contain c cells?
yes
what do thyroid hormones increase?
metabolic activity in almost all tissues and organs
what is the function of calcitonin?
decreases blood calcium concentration by inhibiting the resorption of bone (primarily by inhibiting osteoclast activity)
where are the parathyroid glands found?
four small oval bodies located at the posterior surface of the thyroid gland
what are the cell types found in the parathyroid gland?
chief cells and oxyphilic cells
what do chief cells synthesize?
parathyroid hormone which regulates calcium levels
what regulates the negative feedback loop of the release of calcitonin by c cells and parathyroid hormone by cheif cells?
blood calcium concentrations
what do the adrenal glands consist of?
outer cortex and inner medulla
what are the three zones of the cortex?
the zona glomerulosa (accounting for about 15% of the cortical thickness),
the zona fasciculata (about 75%)
and the zona reticularis(about 10%)
is the zona glomerulosa influenced by ACTH?
nope
what hormones does the cortex produce?
steroids
what do cortical cells contain?
large amounts of smooth endoplasmatic reticulum and lipid droplets
what are the types of corticosteroids?
mineralocorticoids (aldosterone) and glucocorticoids (cortisol)
what is the function of aldosterone?
regulates the resorption of sodium and excretion of potassium in the tubules of the kidney
what is the function of cortisol?
effects protein catabolism in almost all cells aside from liver cells, gluconeogenesis, glycogen storage, mobilisation of fat from adipocytes, anti-inflammatory effects, inhibition of allergic reactions
where are sex hormones produced?
the zona reticularis of the cortex
where are mineralocorticoids produced?
in the zona glomerulosa of the cortex
is the adrenal medulla essential for life?
nah
