Endocrine System Lecture Notes Flashcards

A set of vocabulary flashcards based on lecture notes covering the anatomy of the pituitary gland, hypothalamic connections, and the physiological functions of growth hormone and prolactin.

Endocrine glands

Ductless glands that secrete hormones directly into the blood stream to reach target organs where they exert their action.

Sella turcica

Also known as the hypophysial fossa, it is a small cavity at the base of the skull where the pituitary gland is situated.

Infundibulum

Also called the pituitary stalk, it is the structure that attaches the pituitary gland to the floor of the 3rd ventricle of the brain.

Adenohypophysis

The large anterior lobe of the pituitary gland.

Neurohypophysis

The large posterior lobe of the pituitary gland.

Portal circulation

The presence of $2$ sets of capillaries between $2$ organs, such as between the hypothalamus and the liver.

Median eminence

The basal part of the hypothalamus where arterial twigs from the carotid arteries form a primary capillary plexus.

Hypothalamo-hypophyseal portal circulation

The vascular connection between the hypothalamus and the anterior lobe of the pituitary gland.

Hypothalamo-hypophyseal tract

A nervous connection consisting of a bundle of neurons between the hypothalamus and the posterior pituitary gland.

Somatostatin

Also known as Growth hormone inhibiting hormone ($GHIH$), it inhibits the secretion of $GH$ from somatotropes.

Dopamine

Also known as Prolactin inhibiting hormone ($PIH$), it provides tonic inhibition of prolactin secretion from the hypothalamus.

Gonadotropic hormones

The collective term for Follicle stimulating hormone ($FSH$) and Luteinizing hormone ($LH$), which control the gonads in males and females.

Acidophils

Cells in the anterior pituitary that secrete Growth hormone ($GH$) and Prolactin ($PRL$).

Basophils

Cells in the anterior pituitary that secrete Thyroid stimulating hormone ($TSH$), Adreno-corticotrophic hormone ($ACTH$), and Gonadotrophic hormones ($FSH$ and $LH$).

Somatomedin-C (IGF-I)

Insulin-like Growth Factor-1, produced by the liver in response to $GH$, which stimulates bone thickening and linear growth.

Linear growth

The increase in length of long bones occurring before puberty when the epiphysis and the shaft have not yet united.

Positive nitrogen balance

A state where blood urea nitrogen and amino acid levels decrease because they are being utilized for protein synthesis, stimulated by $GH$.

Diabetogenic hormone

A classification for $GH$ because it increases glucose output from the liver and decreases glucose uptake by cells, acting against insulin.

Hormone sensitive lipase

An enzyme stimulated by $GH$ that leads to lipolysis and the mobilization of free fatty acids ($FFA$).

Ketosis

A condition occurring during hypoglycemia or fasting where excess $GH$ causes the conversion of free fatty acids ($FFA$) into ketone bodies.

Lactogenic hormone

Another term for Prolactin ($PRL$), which is responsible for milk formation by increasing production of casein and lactalbumin.

Amenorrhea

The absence of menstruation caused by Prolactin ($PRL$) inhibiting the effect of gonadotropins ($FSH$ and $LH$) on the ovaries during lactation.

Pituitary Gland Weight

The pituitary gland is a small gland weighing approximately $0.5-1.02,gm$.

Growth Hormone Half-life

The duration of time $GH$ remains in the body before metabolic breakdown is approximately $20,minutes$.