Anatomy- The Endocrine System Flashcards
Hormones
Chemical messengers released to the blood by the cells of endocrine glands that regulate metabolic activities
Hormones signal target cells to perform specific chemical reactions.
Endocrine glands include:
Which organs help with this?
Tissues that produce hormones from within:
Pituitary,thyroid, parathyroid, adrenal, pineal, and thymus.
Organs that help with this are: pancreas, gonads, hypothalamus.
- Tissues that produce hormones from within: adipose cells, small intestine, stomach, kidneys, heart.
Acid-based hormones
Contain a couple to many amino acids
Example: amines, thyroid hormone, peptides
Steroid Hormomes
Synthesized from cholesterol
Eicosanoids
Biologically active lipids released from nearly all cell membranes.
Mechanisms of Hormone action:
- Activate/deactivate enzymes
- stimulate mitosis/cell division
- stimulates synthesis of protein within the cells.
Endocrine System
A system of glands scattered throughout the body that influences the metabolic activities of cells through hormones.
Thyroid Hormone
Binds to a DNA-associated receptor protein which turns on transcription & translation of the associated gene.
Negative Feedback
Thermostat
Humoral Stimuli
Hormone release controlled by blood levels of specific ions and nutrients
Neural Stimuli
Nerve fibers simulate hormone release catecholamines.
Catecholamines are epinephrine and norepinephrine.
Hormonal Stimuli
Other hormones release of a hormone(released by the hypothalamus)
Nervous System Modulation:
The nervous system can override normal homeostatic mechanisms for hormonal control
For example: allow more glucose for fuel to be released during excitement
“Fight or flight” response
Pituitary Gland(anterior pituitary):
Growth Hormone(GH)
Stimulates cell division in most cells.(major targets are bone & skeletal)
IGFs - insulin-like growth factors. Mediates most of the effects of GH
Hypersecretion: can lead to gigantism- long bones develop ACROMEGALY
Hyposecretion: can lead to pituitary dwarfism
Anterior Pituitary: 5 hormones
Name and describe
- Prolactin(PRL) - stimulates milk production by mammary glands
- Follicle-stimulating hormone (FSH)- stimulates gamete production in the gonads.
- Leutinizint hormone(LH) - testosterone, estrogen, progesterone
- Thyroid-stimulating (TSH)
- Adrenocorticotropic hormones (ACTH)- release hormones from Adriano cortex.
Posterior Pituitary(Neurohypophysis):
Receives and stores hormones from hypothalamus for later
Posterior Pituitary(Neurohypophysis): Oxytocin
Produced by the hypothalamus. Stimulates uterine contraction during childhood birth & milk ejection during nursing.
Posterior Pituitary(Neurohypophysis): Antidiuretic Hormone(ADH)
Produced by the hypothalamus.
Stimulates kidney tubules to retain water.
Deficiency of ADH secretion leads to diabetes
Hypothalamus:
List some hormones
GHRH GHIH PRH PIH TRH CRH
Thyroid Gland: Thyroid Hormone
Amino acid hormones containing 2 tyrosine molecules each bound to iodine molecules. Regulates metabolic activities, especially glucose oxidation.
Thyroid Gland: Thyroxine (T4)-
major hormone released from thyroid molecules. ContIns 4 iodine molecules .
Triiodothyronine (T3):
Contains 3 iodine molecules.generally formed from T4.
Simple goiter:
Enlargement of the thyroid gland due to lack of iodine.
Cretinism
Underdeveloped thyroid gland. May lead to mental retardation
Myxedema:
Hypothyroidism in adults(weigh gain, hair loss, slow pulse
Graves’ disease
Hyperthyroidism due to enlarged and overactive thyroid gland
-swelling of the eyes.
Calcitonin
Produces by para-follicular cells(C cells) of thyroid gland.
-lowers blood calcium levels
Parathyroid hormone(PTH) :
Praises blood calcium levels and calcium by kidneys
Adrenal glands(Suprarenal glands)
Pyramids shaped glands. Look like hats above the kidneys.
Adrenal glands: Adrenal Cortex
Releases corticosteroid hormones.
Mineralocorticoids:
Regulate salt in extracellular fluids.
Aldosterone
Primary mineralocorticoid. Enhances sodium from kidney tubules.
Glucocorticoids
Influence metabolism of body cells and help resist stressors.
During times of stress(injury,blood loss), glucocorticoids stimulate gluconeogenesis and mobilize fat and proteins used for energy
Anti-inflammatory agents
Glucocorticoids also prevent water loss from cells into tissue fluids
Gonadocorticoids
Source of sex hormones. Primarily androgens(testosterone) and estrogen.
May cause puberty
Addison’s disease:
Low level of adrenal context hormones resulting in bronzing of skin, low blood sugar.
Cushing syndrome:
High level of adrenal cortex hormones resulting in high blood sugar, high blood sodium, swelling and obesity & and possible masculinization in women.
Adrenal medulla:what does it release?
Describe functions of epinephrine and norepinephrine
Releases catecholamines(norepinephrine and epinephrine)
Epinephrine: stimulates heart rate and metabolism
Norepinephrine: treats low blood pressure and heart failure.
Pancreas:
Releases insulin and glucagon from islets of Langerhans.
Insulin:
Released by beta cells of islets; lowers blood glucose levels by stimulating glucose storage
Insulin deficiency may lead to ________.
Insulin-dependent diabetes mellitus(IDDM).?
Non-insulin dependent diabetes mellitus(NIDDM)?
Diabetes mellitus.
Insulin-dependent diabetes mellitus(IDDM)- autoimmune disease where immune cells attack and destroy beta cells.
Non-insulin dependent diabetes mellitus(NIDDM)- insulin receptors do not properly resolution insulin.
Glucagon
Raises blood glucose levels.
Increases production of glucose in the liver.
Ovaries produce
Estrogens & progesterone(responsible for female reproductive organs)
Insulin inhibits _______.
Inhibits FSH during ovarian cycle
Relaxin
Released during pregnancy. Increases flexibility of pubic symphysis.
Testes produce:
Androgen(male sex hormone)
Testosterone:produced by cells if testes. Is responsible for maturation of male reproductive organs.
produced by cells if testes. Is responsible for maturation of male reproductive organs.
Inhibin:
Inhibits FSH to regulate spermatogenesis.
Pineal gland:
Secretes melatonin.
Melatonin is involved in the sleep/awake cycle.
During sleep, melatonin levels increase
