Exam 6 UC cohort 2027 physio endo (59 ppts)

Hypothalamus Hormones named

TRH

Dopamine

Growth hormone release hormone

Somatostatin

Gonadotropin relase hormone

oxytocin

vasopressin

Pineal gland hormone

Melatonin

Anterior pituitatry hormone

GH

TSH

ACTH

FSH

LH

Prolactin

Posterior Pituitary Hormone

ADH

OXYTOVIN

VASOPRESIN

Thymus hormone

Thymopoeitin

Liver Hormone

IGF ,THPO

Stomach

Gastrin

grehlin

Histamine

Somatostatin

Neuropeptide Hormone

Adrenal hormone

Androgens

glucocorticoids

Adrenaline

Noradrenaline

Kidney Hormone

EPO

Calcitrol

Renin

Testes Hormones

Testosterone inhibin

Estradiol

Pancreas hormone

Insulin

Somatostain

glucagon

Uterus hormones

Relaxin

Prolactin

How do endocrine gland respond to specific signals?

by synthesizing and releasing hormones into the circulation

Endocrine gland are capable of ?

of synthesizing and releasing hormones (special chemical messengers).

Endocrine system functions

–Differentiation of the reproductive and central nervous systems in the developing fetus

–Stimulation of sequential growth and development during childhood and adolescence

–Coordination of the male and female reproductive systems

–Maintenance of an optimal internal environment

–Initiation of corrective and adaptive responses when emergency demands occur

•Chemical messengers that are released by glands

Hormones are

Autocrine

Within cells

Paracrine

Nearby cells

Endocrine communication

Between remote cells

Hormone release is regulated by

–Chemical factors (blood glucose or calcium levels)

–Endocrine factors (a hormone from one gland controlling another endocrine gland)

–Neural control (stress-induced release of catecholamines from adrenal medulla)

blood glucose or calcium levels

Chemical factors

a hormone from one gland controlling another endocrine gland

Endocrine factors

stress-induced release of catecholamines from adrenal medulla

Neural control

–Maintains an optimal internal environment (homeostasis) : positive feedback or negative feedback

•Products of a cycle act upon its gland of origin to shut off secretion (as a means to prevent excess secretion)

Negative Feedback Loops

hormones that have other endocrine glands as their target

Trophic hormone

At which levels negatives feedback is possible

ultrashort (target cells)

short (anterior pituitary gland)

long(hypothalamus)

–Recognize and bind with a high affinity to hormones.

–Initiate a signal transduction into the cell nucleus

Target cells

The more receptors

more sensitive is the cell

True or false : •Hormones Affect Only Cells With Appropriate Receptors

True

Mechanism of hormones

•Act on Cells to Initiate Specific Cell Functions

True or false : Hormones are Chemical Messengers

True

–hormones circulate in free, unbound forms (insulin 3-4 min half-life)

Water-Soluble hormone

–hormones are primarily transported bound to a carrier or transport protein. (half-life of hours to days)

Lipid soluble

Hormones differ by solubility name those class of hormones

Polypeptides (not lipid soluble,bind to receptors on surface of target cells): Secretin

Amino Acids (Epinephrine) : most not lipid soluble bind to receptors on surface of the target cells

steroids(Cortisol) lipids soluble often bind to receptors inside target cells

Steroid and sterols

Pepetides and glycoproteins

Monoamines

Others classification of Hormones

Monoamines hormones

Dopamine

Epinephrine

Melatonin

Norepinephrine

Hormone Receptors: Location

Plasma membrane or in the intracellular compartment of the target cell. May be G protein–linked, ion channels, or enzyme linked.

–Have a high molecular weight.

–Cannot diffuse across the plasma membrane.

•Water-soluble hormones

–Easily diffuse across the plasma membrane and bind to cytosolic or nuclear receptors.

•Lipid-soluble hormones

•Up-regulation

–Low concentrations of hormones increase the # of receptors per cell

–High concentrations of hormones decrease the # of receptors.

•Down-regulation

Specific Rates and Rhythms of Secretion

–(1) Circadian or diurnal patterns - MELATONIN

–(2) Pulsatile and cyclic patterns – secreted in bursts (GH)

–(3) Patterns that depend on circulating substrates (calcium, potassium, or hormones themselves) – CORTISOL

Circadian or diurnal patterns

Melatonin (pineal gland )

Pulsatile and cyclic patterns

Secretes in bursts (GH)

Patterns that depend on circulating substrates

Cortisol

Identify each hormone and their effects on the target cells

•First Messenger

•Hormone that carries the message to the target cell

•Process by which this message is communicated into the target cell

•Involves several steps

•Signal Transduction

Transduction steps

1- Hormone is the first messenger that is secreted into the blood stream

2- Receptors activation of a hormone to its receptor

3- activation of G proteins (Transducer) and membrane associated enzyme (effector enzyme)

4- Production of second messenger

5- Activator of intracellular enzyme such as protein Kinase A or C

6- Alternation in gene transcription and the the resulting target cell response to the hormone

catabolized by circulating enzymes and eliminated in the feces or urine

Peptide hormones are

Metabolized (conjugated) by the liver which inactivates them and renders the hormone more water soluble for renal excretion

Steroid Hormone

Excreted directly by the kidneys

Steroid Hormone

1.Act on preexisting channel forming proteins to alter membrane channel permeability

2- Activating preexisting proteins through a second messenger system

3- Activating genes to cause protein synthesis

Binding of hormones initiates 3 types of effect

1.Direct-changes in cell function

2.Permissive-less obvious hormone changes that affect cell function (insulin increases glucose transport into skeletal muscle cells)

General effects of hormones on target cells:

located at the base of the brain.

Hypothalamus

is located at the sella turcica, a saddle-shaped depression on the surface of the sphenoid bone

Pituitary gland

Hypothalamus Divided into several nuclei and nuclear areas which are :

Supraoptic

Paraventricular

median eminence

How Hypothalamus communicate with the pituitary gland

Via the 03 nucleus (Supraoptic-paraventricular-median eminence)

By which tract The hypothalamus is connected to the posterior pituitary

supraopticohypophysial

The hypothalamus is connected to the anterior pituitary

Blood vessels

•Controlled by the hypothalamus

Pituitary gland

known as the “master gland”

Pituitary gland

–Releasing hormones stimulate the pituitary to produce tropic hormones (hormones that have other endocrine glands as their target)

–Controls many of the other glands of the endocrine system

Pituitary gland

Pituitary Gland Division

Anterior Pituitary

Posterior Pituitary

The basis for central integration of neurologic and endocrine systems

the neuroendocrine system.

Hormones that affect diverse body function

Tropic hormones

•It secretes releasing and inhibiting hormones

Hypothalamus

Hypothalamic-Pituitary Axis

Actions of tropic hormones

In response of the HPA the pituitary releases

____ into general circulation to control activities of other endocrine glands.

Inhibting hormones actions

•Inhibitory hormones suppress pituitary secretions by:

•Inhibiting the pituitary gland

•Inhibiting the hypothalamus

•Inhibitory hormones are a negative feedback mechanism secreted by:

•Target endocrine hormones (ex thyroid)

•Hypothalamus

Secretion of posterior pituitary hormones is controlled by

Nerves reflexes

Not glandular

Posterior pituitary gland

Serves as a site for the secretion of hormones directly into the blood

Neurohypothesis

–Antidiuretic hormone (ADH, arginine vasopressin)

•Controls plasma osmolality.

•Causes water reabsorption in the kidneys.

•Is released when plasma osmolality is increased or intravascular volume is decreased. 

•Causes uterine contractions and milk ejection (let-down) in lactating women.

Reduces the brain’s responsiveness to stressful stimuli, especially in pregnant and postpartum states

–Oxytocin

example of positive feedback.

Oxytocin

Example of hormones control by negative feedback

Thyroid

•Induces milk production during pregnancy and lactation.

Has effects on reproductive and immune functions

Prolactin and Oxytocin

–Melatonin regulates circadian rhythms and reproductive systems, including secretion of GnRH and the onset of puberty.

–Plays an important role in immune regulation.

–Possibly affects the aging process.

Pineal Gland

•Is located within the brain itself.

•Is made up of photoreceptive (light and dark) cells that secrete melatonin.

Pineal Gland