Chapter 16: Endocrine System Flashcards
Study of hormones and endocrine organs
Endocrinology
Endocrinology influences metabolic activities via _____ transported in blood
Hormones
Have ducts (body surface)
Exocrine Glands
No ducts (blood)
Endocrine Glands
DNA → RNA
Transcription
RNA → Protein
Translation
Two main classes of hormones
Amino acid-based & steroids
Second messengers (3)
- cAMP
- PIP2
- cGMP
Factors of target cell activation (3)
- Number of receptors on or in target cell
- Blood levels of hormone
- Affinity between receptor and hormone
As more accumulates, it slows the product
Negative feedback
As more accumulates, it speeds up the product
Positive feedback
Up regulation
Hormone ↓; Receptors ↑
Down regulation
Hormone ↑; Receptors ↓
One hormone can not do its effect without another hormone
Permissiveness
One or more hormones work together towards the same effect
Synergism
Hormones have opposite effect
Antagonism
– Controlled by negative feedback systems
– Vary only within narrow, desirable range
Blood levels of hormones
Endocrine glands synthesize and release
hormones in response to
– Neural stimuli
– Humoral stimuli
– Hormonal stimuli
Neuron → Blood hormone
Neural
Neuron → Blood → Gland → Hormone
Humoral
Neuron → Hormone → Gland → Hormone → Gland → Hormone
Hormonal
Pituitary gland also known as:
Hypophysis
Pituitary gland (hypophysis) has two major lobes:
Posterior lobe (neurohypophysis, pars nervosa) & Anterior lobe (adenohypophysis, pars distalis)
Posterior lobe of the pituitary gland is made up of
Neural tissue
Anterior lobe of the pituitary gland is made up of
Glandular tissue
Hormones of the posterior Pituitary
ADH (antidiuretic hormone
OXY (oxytocin)
ADH (antidiuretic hormone)
prevents urine formation, regulates H2O balance, and targets kidneys
Coffee & alcohol inhibit ADH
OXY (oxytocin)
↑ smooth muscle contraction, milk let down, neurotransmitter in brain, “maternal behavior”, social bonding, and “love”
Anterior pituitary hormones
• Follicle-stimulating hormone (FSH) • Luteinizing hormone (LH) • Adrenocorticotropic hormone (ACTH) • Thyroid-stimulating hormone (TSH) or thyrotropin • Prolactin (PRL) • Endorphins • Growth hormone (GH)
“FLAT PEG”
Thyroid Hormone (TSH)
hypothalamus → TRH troponin → anterior pituitary → TSH → Blood → thyroid gland → thyroid hormone
Growth Hormone (inhibited)
hypothalamus → GH RH → anterior pituitary → GH → bones/muscles
GnRH - Gonadotroponin-RH (FSH, LH)
hypothalamus → Gn RH (FSH RH, LH RH) → anterior pituitary → GN (FSH, LH) → blood → target gonads →
Females: FSH - egg; LH - ovulation
Males: FSH - sperm; LH - testosterone
Prolactin (PRL)
hypothalamus → PRL RH → anterior pituitary → PRL → blood → target
Adrenocorticotroponin Hormone ( ACTH)
hypothalamus → ACTH LH → anterior piuitary → ACTH → blood → adrenal gland → hormones → blood
The adrenal cortex has three layers of cortex that produce different corticosteroids
–Zona glomerulosa—mineralocorticoids
–Zona fasciculata—glucocorticoids
–Zona reticularis—gonadocorticoids
Essential to life, electrolyte balance (Na, K)
Mineralcorticoids
*Cortisol; cortisone; corticosterone; glucogenesis from fats and protein; brain needs glucose
Glucocorticoids
Estrogen; testosterone; onset of puberty, secondary sex characteristics, sex drive in women, post-menopausal estrogen
Gonadocorticoids
Chromaffin cells produce epinephrine and norepinephrine
Dopamine → NE → E
Medulla (Adrenal cortex)
Has both exocrine and endocrine cells
Pancreas
Exocrine and endocrine glands of the pancreas
–Acinar cells (exocrine) produce enzyme-rich
juice for digestion
–Pancreatic islets (islets of Langerhans)
contain endocrine cells Pancreatic islet
- Alpha (α) cells produce glucagon (hyperglycemic hormone)
* Beta (β) cells produce insulin (hypoglycemic hormone)
Found in pancreatic islets (islets of Langerhans)
Produce steroid sex hormones
Gonads
Produce estrogens and progesterone
Ovaries
Secretes estrogens, progesterone, and human chorionic gonadotropin (hCG)
Placenta
