2-Minute Neuroscience: HPA Axis

2-Minute Neuroscience: HPA Axis

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Welcome to 2 minute neuroscience, where I
explain neuroscience topics in 2 minutes or less. In this installment I will discuss the HPA
axis. The hypothalamic-pituitary-adrenal, or HPA,
axis is best known for its role in our body’s reaction to stress. The HPA axis includes a group of hormone-secreting
glands from the nervous and endocrine systems: the hypothalamus, pituitary gland, and adrenal
glands. The hypothalamus is a small neuroendocrine
structure situated just above the brainstem that controls the release of hormones from
the pituitary gland, a hormone-secreting gland that sits just below the hypothalamus. The pituitary gland can release hormones into
the bloodstream to reach a variety of targets. In the case of the HPA axis, hormones released
from the pituitary gland travel down to the kidneys and influence the secretion of hormones
from endocrine glands called the adrenal glands, which sit on top of the kidneys. The primary function of the HPA axis is to
regulate the stress response. When we experience something stressful, the
hypothalamus releases a hormone called corticotropin-releasing hormone (or CRH). CRH signals the pituitary gland to secrete
a hormone called adrenocorticotropic hormone, or ACTH into the bloodstream. ACTH travels down to the adrenal glands where
it prompts the release of a hormone called cortisol from the cortex, or outer layer,
of the adrenal glands. The release of cortisol causes a number of
changes that help the body to deal with stress. For example, it helps to mobilize energy like
glucose so the body has enough energy to cope with a prolonged stressor. When cortisol levels in the blood get high,
this is sensed by receptors in areas of the brain like the hypothalamus and hippocampus,
which leads to the shutting off of the stress response through what is known as a negative
feedback mechanism.

34 thoughts on “2-Minute Neuroscience: HPA Axis”

  1. @neuroscientifically challenged…………. Thank you very much for all of your videos……… Almost after three weeks…. Now there is a new video…….makes life easy….. Have a nice day

  2. Woah. Great job again man. I just got a bit lost the last 5 seconds but I will read the transcript to clarify 🙂 THANKS BUDDY!!!

  3. Didn't know I had a second nut sack in my brain, you learn something new everyday!

    Edit: Thank you for the video.

  4. I read that the hpa axis can be permenqntly damGed by childhood stress. Would this mean a constant state of hpa arousal in adulthood?

  5. For a Biochemist Ph D – this is a true pleasure watching you doing this. Great Talent! Become a Prof. of Biochemistry!

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