733 Endocrine System

endocrine system

a complex network of glands that produce and secrete hormones directly into the circulatory system

endocrine glands

secrete hormones directly into the circulatory system

exocrine glands

discharge their products which may or may not be hormones into ducts

hormones

chemical messengers released by endocrine cells into the bloodstream to coordinate fluid function across organs and act on specific target tissues

peptides/proteins

water soluble; stores in vesicles; rapid onset; blind cell-surface receptors

steroids

lipid soluble; synthesized on demand; blind intracellular

amines

can act like peptides or steroids

what triggers hormonal release

• neural input

• fluid composition signals

• hormonal release

transport in blood

water-soluble hormones travel free

lipid-soluble mostly protein bound

cell-surface receptors

activate second messengers leading to fast changes in enzyme activity, ion flux, and transporters

intracellular/nuclear receptors

hormone-receptor complex binds DNA, alters cellular gene transcription then has slower, longer lasting effects

hypothalamus location

base of the brain

hypothalamus function

Controls many of the body’s hormonal functions by regulating the pituitary gland. It links the endocrine and nervous systems through a stalk like structure called the infundibulum, ensuring they work in synergy

what hormones does the hypothalamus release

• corticotropin-releasing hormone (CRH)

• thyrotropin-releasing hormone (TRH)

• gonadotropin-releasing hormone (GnRH)

• growth hormone-releasing hormone (GHRH)

• somatostatin

• oxytocin

• antidiuretic hormone

Corticotropin-Releasing Hormone

triggers the release of ACTH from the pituitary

Thyrotropin-Releasing Hormone (TRH)

promotes the sectrion of thyroid stimulating hormone from the pituitary

Gonadotropin-Releasing Hormone (GnRH):

controls the release of luteinizing hormone and follicle stimulating hormone from the pituitary gland

growth hormone-releasing hormone (GHRH)

stimulates the release of growth hormone

somatostatin

inhibits the release of growth hormone and thyroid-stimulating hormone

oxytocin

while primarily known for its role in childbirth, it also plays a role in social bonding, stress reduction, and even pain modulation

antidiuretic hormone

regulates water balance in the body, impacting blood pressure regulation and overall fluid homeostasis

hypothalamus relevance to PT

Provides context to when a patient presents fatigue, weakness, or poor recovery; it plays a critical role in regulating the body’s homeostasis

pituitary gland location

base of the brain just below the hypothalamus

pituitary gland function

Secretes hormones that influence numerous other endocrine glands. It has roles in growth, blood pressure regulation, reproductive function, etc.

what hormones does the anterior pituitary gland secrete

• growth hormone

• thyroid stimulating hormones (TSH)

• adrenocorticopic hormone (ACTH)

• follicle stimulating hormone (FSH)

• Luteinizing hormone (LH)

what hormones does the posterior pituitary gland secrete

• Antidiuretic hormone (ADH)

• Oxytocin

anterior pituitary function

regulated through a hypothalamic-hypophyseal system where hypothalamus neurons release “releasing” or “inhibiting” hormones into this portal circulation

posterior pituitary function

hormones are synthesized in the hypothalamic neurons which travel down the infundibulum and are stored in the posterior pituitary until released directly into circulation

growth hormone

stimulates growth of the skeletal system and general growth of muscle and other tissues; increases rate of protein synthesis, mobilizes fats for use of fat as fuel; decreases carbs use for fuel

thyroid stimulating hormone

stimulates the release of T3 & T4 released by the thyroid gland

Adrenocorticopic Hormone (ACTH)

regulates the release of glucocorticoids from the adrenal cortex

follicle-stimulating hormone

initiates release of the follicles and promotes secretion of estrogen in the ovaries in women and stimulates sperm production in men

Luteinizing hormone (LH)

causes follicle to rupture, stimulating ovulation; promotes secretion of estrogen and progesterone; causes testes to secrete testosterone

prolactin

secreted by the anterior lobe, governs milk production in breastfeeding women however non-pregnant individuals can indicate pituitary disorders

pituitary gland relevance to PT

Symptoms can range from fatigue, muscle weakness, to altered pain perception which directly intersect with therapeutic implications

thyroid gland location

situated in the lower neck, wrapped around the trachea

parathyroid gland location

situated at the posterior aspects of the thyroid gland

thyroid function

regulates metabolism, energy production, and calcium balance. Secretes hormones like thyroxine and triiodothyronine

parathyroid function

control and maintain precise levels of calcium in the blood

what hormones does the thyroid secrete

T3, T4, calcitonin

what hormones does the parathyroid gland secrete

parathyroid hormone

T3 & T4 hormone

increases rate of cellular metabolism; for body temperature regulation

calcitonin

decreases calcium concentration in the blood by increasing osteoblast

parathyroid hormone

increases calcium concentration in the blood by increasing osteoclast activity; also increases calcium absorption from intestines and kidneys

parathyroid relevance to PT

have a crucial role in maintaining calcium homeostasis which is critical for bone integrity, muscle function, and neuromuscular health

thyroid relevance to PT

with its central role in metabolism and energy regulation, has a multitude of implications for PT such as energy and fatigue, muscle function, bone health, body weight and composition, temperature sensitivity, and joint and muscle pain

suprarenal glands location

positioned atop the kidneys

suprarenal glands function

plays a pivitol role in stress response, metabolism, and overall homeostasis

what glands does the adrenal cortex secrete

• cortisol

• aldosterone

• androgens

what glands does the adrenal medulla secrete

catecholamines (epinephrine & norepinephrine)

cortisol

regulates metabolism, reduces inflammation, and aids in memory formulation

what could elevated cortisol lead to

over extended periods of time can lead to muscle breakdown, fatigue, and prolonged recovery time

aldosterone

manages salt and water balance, thereby controlling blood pressure. it ensures the kidneys retain sodium while excreting potassium

androgens

the adrenal cortex also produces small amounts of male and female sex hormones which can influence muscle mass, bone density, and overall energy levels

catecholamines (epinephrine & norepinephrine)

elevate heart rate, boost energy supplies, and prepare the body for swift action

suprarenal glands relevance to PT

relevant to stress and recovery, fluid balance and muscle function, cardiovascular health, hormonal balance, and chronic conditions

pancreas location

deep within the abdomen behind the stomach

pancreas function

vital for glucose regulation, secreting insulin and glucagon

what hormones does the pancreas secrete

insulin and glucagon

insulin

decrease blood glucose levels; increases use of glucose as fuel or storage as glycogen

glucagon

stimulates gluconeogenesis and glycogenolysis in the liver and lipolysis in adipose tissue to maintain blood glucose levels

pancreas relevance to PT

relevant to PT because crucial in maintaining energy regulation and wound healing, neuropathic concerns, muscle function, and bone health

gonads

comprised of the testes in males and ovaries in females

testes location

housed within the scrotum and hang external to the body

ovaries location

positioned on either side of the lower abdomen, adjacent to the uterus

what hormones do the testes secrete

testosterone, inhibin

what hormones do the ovaries secrete

estrogen, progesterone, inhibin, relaxin

testosterone function

male sex hormone responsible for the primary and secondary sex characteristics. Also plays a role in fat distribution, red blood cell production, maintaining bone density, mood, energy levels, and cognitive function

inhibin function

regulates the production of FSH by the anterior pituitary gland

estrogen function

promotes female reproductive growth and development, regulates menstrual cycle and pregnancy; maintains bone mineral content; distributes fat in adipose tissue

progesterone

regulates menstrual cycle and pregnancy, prepares breasts for lactation

gonads PT relevance

they influence on muscle development, bone health, and even mood underscores the interconnected nature of human physiology

thymus location

the upper chest, just behind the sternum, that plays a central role in immune system development

thymus function

responsible for the maturation of T-lymphocytes, crucial for adaptive immunity

thymus relevance to PT

relevance to PT include age-related changes because the aging shrinks the thymus resulting in a weaker immune system and immunodeficiency conditions

pineal gland location

inferior to the middle brain

pineal gland function

regulates sleep and circadian rhythms

pineal gland PT relevance

relevance to PT includes sleep regulation, circadian rhythms, effects of light, and bone health