Lecture 36: Adrenal glands, adrenaline, cortisol and stress

Growth hormone receptors become functional homodimers when GH is present.

The adrenal cortex and adrenal medulla derive from [blank_start]different[blank_end] embryonic tissue. The cortex is [blank_start]yellow[blank_end], while the medulla is [blank_start]red or grey[blank_end].

Choose the incorrect statement about the adrenal cortex.

Choose the correct statements about the adrenal medulla.

Cortisol travels bound to a carrier protein.

Cortisol is a [blank_start]steroid[blank_end] hormone which can permeate the membrane. Within the [blank_start]cytoplasm[blank_end], it binds to a mobile [blank_start]receptor[blank_end], and forms a hormone-receptor complex that migrates to the [blank_start]nucleus[blank_end] and binds to DNA at [blank_start]specific[blank_end] sites. Specific genes are activated to up-regulate [blank_start]transcription[blank_end] of mRNA. In the cytoplasm, mRNA [blank_start]translates[blank_end] and synthesizes a new protein.

Choose the incorrect statement about the indirect effects of cortisol via proteins.

The effects or cortisol are slow (hours to days).

Either stress or non-stress neural inputs (e.g. circadian rhythm or [blank_start]low[blank_end] blood glucose level) can stimulate the [blank_start]hypothalamus[blank_end] to release [blank_start]corticotropin[blank_end] releasing hormone (CRH). CRH travels via capillaries to the [blank_start]anterior[blank_end] pituitary gland and [blank_start]stimulates[blank_end] of adrenocorticotropic hormone (ACTH). ACTH travels via the bloodstream and reaches the kidney's [blank_start]adrenal glands[blank_end] where it stimulates release of cortisol.

The metabolic effects of cortisol [blank_start]inhibit[blank_end] glucose uptake by cells in muscle and fat. In skeletal muscle, there is also stimulation of protein [blank_start]synthesis[blank_end], and in fat, there is also stimulation of [blank_start]triglyceride[blank_end] breakdown. In the [blank_start]liver[blank_end], gluconeogenesis is [blank_start]enhanced[blank_end]. The other effects of cortisol are that it aids in coping with stress in the [blank_start]short[blank_end] term and that it [blank_start]suppresses[blank_end] the immune system in the [blank_start]long[blank_end] term.

(Choose all correct statements). Cortisol secretion:

Irregular sleep will affect the pattern of cortisol secretion.

Which of these are NOT functions of cortisol?

Which of these is not an effect of low cortisol levels?

Addison's disease results from adrenal [blank_start]cortex[blank_end] dysfunction: low cortisol and aldosterone levels. Low cortisol levels mean that cortisol will not properly feed back negatively to the [blank_start]anterior pituitary gland[blank_end], meaning more ACTH (adrenocorticotropic hormone) is released into the blood. ACTH stimulates melanin synthesis and bronzing of the [blank_start]skin[blank_end] is observed. Other symptoms include [blank_start]low[blank_end] blood glucose level, low blood pressure, fatigue, weakness, and unexplained [blank_start]weight[blank_end] loss.

Overproduction of ACTH due to low cortisol levels in the blood can lead to a high sodium, low potassium content in the blood.

Cushing syndrome is a result of [blank_start]too much[blank_end] cortisol. Symptoms include [blank_start]high[blank_end] blood pressure and glucose levels, weakness, fat deposition in the face, neck and trunk (particularly [blank_start]abdomen[blank_end]), edema (swelling), muscular [blank_start]atrophy[blank_end], and [blank_start]loss[blank_end] of bone mass.

Adrenaline is a peptide hormone.

Adrenaline acts via a secondary messenger.

Adrenaline alters enzyme activity in the liver to inhibit glycogenolysis.

Response to adrenaline acts in seconds or minutes.

Adrenaline is an exception to peptide hormones as it is stored.