Ch.17 The Endocrine System Saladin Anatomy & Physiology

Why is Cell Communication important?

internal communication is necessary for coordination of cell activities

What are the four principal mechanisms of communication between cells?

Gap Junctions, Neurotransmitters, Paracrine (local) Hormones, and Hormones.

How does a Gap Junction communicate between cells?

pores in cell membrane allow signaling molecules, nutrients

How does a Gap Junction communicate between cells?

electrolytes to move from cell to cell

How does a Neurotransmitter communicate between cells?

released from neurons to travel across synaptic cleft to second cell

How does a Paracrine (local) Hormone communicate between cells?

secreted into tissue fluids to affect nearby cells

How do Hormones communicate between cells?

chemical messengers that travel in the bloodstream to other tissues and organs

What are the components of the Endocrine System?

glands, tissues, and cells that secrete hormones

Endocrinology

What type of Glands has organs that traditional sources of hormones

Endocrine Glands

What type of Glands has organs that traditional sources of hormones?

Hormones

chemical messengers that are transported by the bloodstream is known as ______.

Hormones

what chemical messengers stimulate physiological responses in cells of another tissue or organ, often a considerable distance away?

Exocrine Glands

What type of glands have ducts?

Exocrine Glands

What type of glands carry secretion to an epithelial surface or the mucosa of the digestive tract:

- ex: "external secretions"

Exocrine Glands

What type of glands have Extracellular effects (food digestion)?

Endocrine Glands

What type of glands do not have ducts?

Endocrine Glands

What type of glands Contain dense, fenestrated capillary networks which allow easy uptake of hormones into bloodstream?

Endocrine Glands

What type of glands have · "Internal secretions"?

Endocrine Glands

What type of glands have Intracellular effects such as altering target cell metabolism?

Liver Cells

what type of cells defy rigid classification?

Liver Cells

what type of cells classification—releases hormones, releases bile into ducts, releases albumin and blood-clotting factors into blood?

Liver Cells

What type of cells are not hormones?

Nervous & Endocrine Systems

What two systems serve for internal communication?

The Nervous System reacts quickly (ms timescale), stops quickly

What is the Nervous System's reaction according to Speed and persistence of response?

The Endocrine System reacts slowly (seconds or days), effect may continue for days or longer

What is the Endocrine System's reaction according to Speed and persistence of response?

The Nervous System response declines (adapts quickly)

What is the Nervous System's reaction according to Adaptation to long-term stimuli?

The Endocrine System response persists (adapts slowly).

What is the Endocrine System's reaction according to Adaptation to long-term stimuli?

The Endocrine System response is general, widespread effects (many organs).

What is the Endocrine System's reaction according to Area of effect?

The Nervous System response is targeted and specific (one organ).

What is the Nervous System's reaction according to Area of effect?

Norepinephrine, dopamine, and antidiuretic hormone

What are the three chemicals that function as both hormones & neurotransmitters?

Norepinephrine and glucagon

What are the two similar effects on target cells?

Norepinephrine and glucagon

What are the two similar effects on target cells that causes glycogen in the liver?

Nervous & the Endocrine Systems

What two systems can regulate each other?

Neurotransmitters can affect glands

How does the Nervous System regulate the Endocrine System?

Hormones can affect neurons

How does the Endocrine System regulate the Nervous System?

Neuroendocrine cells

What type of cells share characteristics between both the Nervous & Endocrine Systems?

Neuroendocrine cells

What type of cells are Neuron-like cells that secrete oxytocin into blood?

Neuroendocrine cells

What type of cells involves the interaction between the nervous system and the hormones of the endocrine glands?

Target organs or cells.

organs or cells that have receptors for a hormone and can respond to it

Some target cells possess enzymes that convert a circulating hormone to its more active form are known as _______ ________ or ________.

Target Cells

What type of cells posses enzymes that convert a circulating hormone to its more active form?

Hypothalamus

The ___________ is shaped like a flattened funnel.

Hypothalamus

The _________ Forms floor and walls of third ventricle of brain.

Hypothalamus

What Regulates primitive functions from water balance and thermoregulation to sex drive and childbirth?

Hypothalamus

Many of the ________ functions are carried out by pituitary gland.

The Pituitary Gland

What is suspended from hypothalamus by a stalk?

Infundibulum

What is the name of the stalk that is suspended from the hypothalamus?

Sella Turcica of sphenoid bone

Where is The Pituitary Gland "housed" located?

The pituitary gland is the size and shape of a kidney bean.

What is the size and shape of the pituitary gland?

pituitary gland

What is Composed of two structures with independent origins and separate functions?

Adenohypophysis (anterior pituitary)

Neurohypophysis (posterior pituitary)

What are the names of the two structures with independent origins and separate functions that make up the pituitary gland?

Adenohypophysis

What is the anterior lobe of the pituitary gland?

Adenohypophysis

____________________ is Linked to hypothalamus by hypophyseal portal system.

Portal Venules

Primary capillaries in hypothalamus connected to secondary capillaries in adenohypophysis by _____________.

adenohypophysis cells

Hypothalamic hormones regulate what type of cells?

In hypophyseal portal system from hypothalamus to anterior pituitary

How do Hypothalamic-releasing and -inhibiting hormones travel?

anterior pituitary

Different hormones are secreted by _______ pituitary

Neurohypophysis

What is the posterior lobe of the pituitary gland?

Neurohypophysis

What pituitary gland is not a true gland?

Neurohypophysis is made up of nerve tissue.

Why is Neurohypophysis not a true gland?

Nerve cell bodies in hypothalamus pass down the stalk

How do Nerve cell bodies travel in hypothalamus?

hypothalamo-hypophyseal tract

Nerve cell bodies in hypothalamus pass down the stalk as ________________.

in the posterior lobe go the pituitary gland

Where do nerve cell bodies "end" when traveling in the hypothalamus?

The pineal gland's function

circadian rhythms of physiological function

The pineal gland's Secretes

Melatonin

What is melatonin

24 hour circadian cycle/rythem. Sleep/wake cycle

When is melatonin produced?

dark or night time

The pineal gland is located

attached to the roof of the third ventricle beneath the posterior end of the corpus callosum

The thymus is located

is a bilobed gland in the mediastinum superior to the heart, behind the sternal manubrium

The thymus plays in what three systems?

endocrine, lymphatic, and immune systems.

The thymus size of an infant is?

large

The thymus size of in an elderly person is?

small

The thymus has a site for what?

maturation for T cells

T cells are critically important

for immune defense.

The thymus secretes

thymosin, and thymulin,

what do thymosin and thymulin stimulate

the development of other lymphatic organs and development and activity of T cells.

The thyroid Gland is

the largest endocrine gland in adults

the thyroid is composed of ___ lobes?

2

what is named for the childlike ______ cartilage of the larynx.

thyroid

thyroid: the two lobes are usually joined by a narrow anterior bridge of tissue, the _____

isthmus

are filled with a protein rich colloid is known as ________ _________

thyroid follicles

what lines follicular cells in the thyroid?

simple cuboidal epithelium of follicular cells.

The thyroid gland secretes

thyroxine (T4, tetraiodothyronine) and triiodothryonine (T3)

Why does the thyroid gland secrete T3 & T4?

because they secrete thyroxined in response to TSH from the pituitary, and the primary effect of TH is to increase the body's metabolic rate.

What is another name for T3?

triiodothyronine

Why is there T3?

Because of three iodine atoms

Why is there t4?

Because of four iodine atoms

What is another name for T4?

tetraiodothyronine

TH raises oxygen consumption and has a calorigenic effect, what is this effect?

it increases heat production.

what gland contains all of these structures/cells nests of C (clear) cells, or parafollicular cells, between the follicles?

The thyroid gland

What cells secrete calcitonin in response to rising levels of blood calcium?

Parafollicular Cells/CCells

What cells stimulates osteoblast activity and calcium deposition while antagonizing the action of parathyroid hormone.

Parafollicular Cells/CCells

The parathyroid glands are usually how many

4

parathyroid glands are located

are found partially embedded in the posterior surface of the thyroid

parathyroid hormone (PTH) is secreted

in response to low blood calcium.

Why will PTH stimulate osteoclast?

To go through the blood stream to raise the calcium level to its homeostasis level.

Where are the adrenal (suprarenal) glands located?

sit like caps on the superior to superomedial surface of each kidney.

The adrenal Glands are

Like the kidneys, they are retroperitoneal.

The adrenal medulla has a dual nature,

acting as both an endocrine gland and as a ganglion of the sympathetic nervous system.

Sympathetic preganglionic nerver fibers extend through the cortex to reach chromaffin cells in the _______ __________

adrenal medulla

modified sympathetic postganglionic neurons are called __________ ________

Chromaffin Cells