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