is the only biologically active form of thyroid hormones.

is all protein bound in the circulation

is formed from T4 in target cells

binds only to plasma membrane receptors

T3 is more abundant than T4

they decrease the BMR

they decrease the GIT motility

T3 is more active than T4

Has less affinity to receptors than T4

Is liberated from thyroglobulin by the action of proteinase enzyme

Binds to plasma membrane receptors

Stimulates the secretion of TSH by anterior pituitary

bound to globulin

bound to albumin

bound to prealbumin

unbound

activation of thyroid follicular cells

conversion of T4 to T3

Increasing thyroglobulin synthesis

Increasing release of T3, T4

Thyroid stimulating hormone (TSH)

Somatomedins

Adrenocorticotropic hormone (ACTH)

Follicle stimulating hormone (FSH)

Dopamine

Growth hormone releasing hormone (GHRH)

Thyroid-stimulating hormone (TSH)

Gonadotropin-releasing hormone (GnRH)

Develop acromegaly

Be of a short stature with abnormal body proportions

Excrete a large amount of diluted urine

Have normal sexual and mental development

Releasing and inhibiting hormones from the hypothalamus

Direct neural stimulation of the hypothalamus

cAMP from the hypothalamus

The posterior pituitary

Follicle stimulating hormone

Luteinizing hormone

Prolactin

Vasopressin

Oxytocin stimulates milk synthesis by the breast.

They are formed by the hypothalamus.

Deficiency of Anti-diuretic hormone (ADH) results in decreased production of urine.

Secretion of Oxytocin and ADH is regulated by releasing hormones.

Due to decrease of growth hormone secretion

Characterized by an increase in basal metabolic rate

Characterized by mental retardation

Normal mentally and sexually.

Hypoglycemia

Overgrowth of long bones

Increased growth of soft tissue

Mental retardation

Short stature and normal mentality

Mental retardation

Hypogonadism only

Short stature and hypogonadism.

Causes depression of mental function

Depletes fat stores

Increases body weight

Produces hypothermia.

Administration of an inhibitor of angiotensin- converting enzyme (ACE)

Increased plasma Na+ levels

Decreased plasma K+ level

Decreased plasma volume

is liberated from thyroglobulin by the action of peroxidase enzyme

Increases the body needs for vitamins:

Acts on nuclear receptors only which produce its genomic and non-genomic actions

Has more affinity to receptors than T3

Insulin and IGF-1 act on the same receptors.

Insulin release from 3 cells is decreased by inactivating ATP-sensitive K+ channels

Affinity of insulin receptors is increased by excess glucocorticoids

Insulin facilitates glucose entry in the brain by increasing number of GLUT4

Since birth produces cretinism which is mentally normal but sexually retarded

Produces Increased metabolic rate

In an adult produces shortened reflex reaction time

Produces coarse skin with non-pitting edema

Is characterized by increased energy expenditure and cold, pale, dry skin

Is accompanied by a rise in systolic and diastolic blood pressure

May be associated with exophthalmos due to antibodies against extraocular muscles

Due to pituitary thyrotrope tumor is accompanied by High T3 and T4 with low TSH

Secretion is increased by stimulation of a-adrenergic receptors

Feedback mechanism is important mainly during stressful conditions

Increases the breakdown of muscle glycogen

Secration is directly proportional to the blood glucose level