Untitled Flashcards Set

A key principle of homeostasis is that physiological systems can be modulated via __ loops.

feedback

Maintenance of a relatively constant internal environment relies on __ feedback loops to keep a controlled variable within the normal physiological range.

negative

In contrast to negative feedback loops, __ feedback loops accelerate changes in the internal environment.

positive

The synthesis and/or secretion of hormones can be regulated by direct feedback loops and __ feedback loops.

order

Direct feedback loops and first order feedback loops are both characterised by only __ control point.

one

__ feedback loops are defined by having two control points.

Second order

The vast majority of endocrine axes in vertebrates are regulated through __ order feedback loops.

second or third

For a direct feedback loop, a physiological stimulus directly stimulates an endocrine gland to synthesize __ into the circulatory system.

hormones

__ is the only true example of a direct feedback loop in mammals. (explain)

Atrial natriuretic peptide (ANP)It is secreted by the heart in response to increased blood volume, directly influencing its own secretion by affecting target organs.

The role of the __ is to detect changes in the controlled variable in feedback loops.

sensor

In a second order feedback loop, the integrator sends a signal to an __ endocrine gland.

intermediary

In a third order feedback loop, hormone 1 is carried to a __ endocrine gland by the circulatory system.

second intermediary

The hypothalamus forms part of the __ and contains clusters of specialist _ neurones.

diencephalon, magnocellular

The posterior pituitary lobe is also known as the __.

neurohypophysis

The anterior pituitary lobe is also known as the __.

adenohypophysis

Magnocellular neurones with cell bodies in the hypothalamus send axons to the __ pituitary gland.

posterior

The anterior pituitary cells are connected to the hypothalamus through the __ circulation. which starts with capillaries in the (base) of the hypothalamus and ends with capillaries that drain into the _

hypothalamo-hypophyseal portal, median eminence, adenohypophosis

The hypothalamus synthesizes and secretes __ hormones that act on the anterior pituitary gland.

hypophysiotropic

The hormone __ inhibits adenohypophyseal hormone synthesis/secretion.

dopamine

No releasing hormone has been identified for __.

prolactin (PRL)

GHIH acts as an antagonistic partner to __.

GHRH

is a hormone produced by lactotropes in response to hypothalamic control.

Prolactin (PRL)?

TSH stimulates the __ gland to produce thyroid hormones.

thyroid

what stimulates the adrenal cortex to secrete cortisol.

adrenal

GH directly influences __ growth and indirectly promotes growth through IGFs.

body

FSH acts on the granulosa cells of the __.

ovary

LH indirectly regulates female sexual receptivity and stimulates __ synthesis.

progesterone

In long loop negative feedback, the end organ hormone suppresses the relevant __ hormone.

hypothalamic

In short loop negative feedback, the feedback loop runs from the anterior pituitary to the __.

hypothalamus

The circadian rhythm of cortisol has its highest plasma concentration upon __.

waking

Cortisol exerts long loop negative feedback on both __ and anterior pituitary hormones.

hypothalamic

Neuroendocrine cells release small peptide hormones into the __ circulation.

local or systemic

The primary physiological role of oxytocin is to induce contractions in the __.

uterus

AVP acts as an anti-diuretic hormone by facilitating water __ in the kidneys.

resorption

The release of neurohypophyseal hormones can be regulated by __ reflexes.

neuroendocrine

The Fergusson reflex is crucial for the safe birth of an __ mammal.

infant

Suckling reflex increases secretion of OT, promoting __ in mammals.

milk ejection

In the adrenal medulla, increased sympathoadrenal stimulation results in increased secretion of __.

adrenaline

The synthesis of adrenaline is pivotal in the fight or flight response, mobilizing __ stores.

glucose

The hypothalamus contains distinct __ in its structure that produce different hormones.

nuclei

The infundibulum connects the hypothalamus to the __ gland.

pituitary