Unit 1: Endocrine System Flashcards
Define gap junction
“Channel” in cell membrane which directly connects cells together, linking them electrically and metabolically
Define Paracrine Hormones
AKA Local Hormones
Communicate to nearby cells across synapse, only travelling a short distance
Define Endocrine Hormones
“Long distance” communication
Hormones are secreted directly into the bloodstream to affect target cells
What is the difference between the Nervous System and Endocrine System?
Endocrine system has widespread, general effect on many organs
Nervous system has targeted and specific effects on 1 organ or tissue
Endocrine system’s effects are slow and long-lasting
Nervous system’s effects are rapid and stop quickly
What are the similarities between the Nervous System and Endocrine System?
Some chemicals can be hormones AND neurotransmitters
Some hormones are secreted by “neuroendocrine “ cells (bit of both)
The 2 systems can have overlapping results on the same organs
The 2 system can regulate each other
How do the Nervous and Endocrine systems regulate eachother?
Neurons can trigger hormone secretion
Hormones can inhibit or stimulate neurons
Give an example of overlapping effects of the Nervous and Endocrine system
In “fight or flight,” endocrine and nervous system can release the same chemicals in response to a stimuli, like glycogen to up the glucose level in the blood to prepare for energy exertion
What hormones are secreted by neuroendocrine cells
Oxytocin
Antidiuretic hormone
What does antidiuretic hormone do?
Tells body to decrease urine production
What are the 3 components of the Endocrine System?
Endocrine glands
Hormones
Target cells
What do endocrine glands do?
Produce hormones
Define hormone
Chemical messenger secreted into the blood to stimulate a response
Define target cell
A cell with hormone receptors which respond
What are the 3 types of hormone release?
Neurally
Humorally
Hormonally
What does Neurally mean in relation to hormone release?
The secretion or inhibition of hormones is influenced by emotion or stress
What does Humorally mean in relation to hormone release?
The secretion or inhibition of hormones is dependent on the concentration of other NON-hormonal substances in the blood
What does Hormonally mean in relation to hormone release?
Hormones are regulated by other hormones
What are Tropic hormones?
Hormones that regulate other hormones
What does the Hypothalamus regulate?
Primitive Functions like water balance, sex drive, etc.
The __________ carries out function for the Hypothalamus
Pituitary Gland
Where is the Pituitary Gland located?
Suspended off the Hypothalamus
What connects the Pituitary Gland to the Hypothalamus?
Infundibulum
Describe the lobes of the Pituitary Gland
Posterior:
Not actually a gland, but an extension of the hypothalamus
Anterior:
True endocrine gland
What is the Hypothalamo - Hypophyseal Tract?
Axons extending from the Hypothalamus to the posterior Endocrine “gland”
Which hormones does the posterior Pituitary Gland store and release?
Oxytocin
Antidiuretic hormone
What does Oxytocin do?
Hormone responsible for deep emotional bonding, labor contractions, and lactation
What is the Hypothalamo - Hypophyseal Portal System?
Capillaries which carry hormones from the Hypothalamus to the anterior Pituitary Gland
How many capillary beds does the Hypothalamo - Hypophyseal Portal System have?
2 capillary beds
What do Hypothalamic hormones do?
Release/inhibit other hormones
Portal System hormones, -RH means ______ and -IH means ——
Release hormone
Inhibit hormone
Name 6 anterior Pituitary Gland hormones
FSH (follicle stimulating hormone)
LH (luteinizing hormone)
TSH (Thyroid stimulating hormone)
ACTH (adrenocorticotropic hormone)
GH (growth hormone)
PRL (prolactin)
What are the 2 gonadotropins?
LH and FSH
What does FSH do in females and males?
Female - stimulates development of eggs and follicles in the ovaries
Male - stimulates production of sperm in testes
What does LH do in female and males?
Female - stimulates ovulation and secretion of estrogen and progesterone
Male - stimulates interstitial cells in testes to secrete testosterone
What does TSH do?
Stimulates growth of the thyroid gland
Stimulates secretion of thyroid hormone (T3 and T4)
What does ACTH do?
Regulates response to stress by stimulating Adrenal Gland cortex with corticosteroids that regulate glucose, fat, and protein metabolism
What does GH do?
Promotes tissue growth
What does PRL do?
Milk production in females
Increased sensitivity to LH in males causing testosterone to increase
Most anterior Pituitary Hormones are _____
tropic
Define hydrophobic hormones and describe how they work? Travel?
Hormones derived from cholesterol which are lipid soluble (water INsoluble)
Move directly through phospholipid bi-layer and act via INTRAcellular receptors (usually acting on gene transcription within the cell)
Must bind to a blood plasma transport protein to be transported across body (bound) OR can travel very short distance unbound
Define hydrophilic hormones and describe how they work? Travel?
Hormones derived from polypeptides and proteins which are water soluble (lipid INsoluble)
Cannot move directly through phospholipid bi-layer, so attaches to membrane-bound receptors and modifies existing metabolic protein to trigger events inside the cell to occur
Define hydrophilic hormones and describe how they work? Travel?
Hormones derived from polypeptides and proteins which are water soluble (lipid INsoluble)
Cannot move directly through phospholipid bi-layer, so attaches to membrane-bound receptors and modifies existing metabolic protein to trigger events inside the cell to occur
Since it is water soluble, these hormones dissolve easily with blood plasma for transport
Define intracellular receptor
Hormone receptors inside cell which turn cell activity on/off
Define membrane-bound receptor
Hormone receptors outside the cell ON the plasma membrane of target cells which turn cell activity on/off
Where is the Thyroid Gland?
Located in the neck, below the larynx
What hormones do the Thyroid Gland produce and how is their secretion controlled?
T3 and T4
Hormonally
Also calcitonin
Humorally
What are T3 and T4 hormones for? What does it target?
Metabolism, growth, and development
Widespread
What is Calcitonin hormone for? What does it target?
Decreases blood calcium levels by depositing calcium into bones (target)
Where are the Parathyroid Glands?
Located on the Thyroid Gland (but separate)
What hormone(s) do the Parathyroid Glands produce?
Parathyroid Hormone (PTH)
What does Parathyroid Hormone (PTH) do and what does it target?
Increases blood calcium levels
Targets bones (inc. osteoclast activity), kidneys (dec. calcium in urine), and intestines (inc. calcium absorption)
Where are the Adrenal Glands?
Above each kidney
Define HPA Axis
Hypothalamo - Pituitary - Adrenal Axis
Complex set of interactions between the 3
Where are the 2 parts of the Adrenal Glands?
Adrenal cortex (outside, glandular)
Adrenal Medulla (inside, neural)
What does the Adrenal Cortex produce?
STEROIDS
Mineralocorticoids (aldosterone)
Glucocorticoids (cortisol and cortisone)
Tiny bit of sex hormones (androgen + estrogen)
What does the Renin-Angiotensin System control?
Regulates blood pressure
What is aldosterone’s role in the Renin-Angiotensin System?
Released by the Adrenal Cortex to prevent water reabsorption by INCREASING Na+ absorption and SECRETING K+ to help with blood volume
What is the function of glucocorticoids?
Cortisol and cortisone are hyperglycemic hormones that increase blood sugar to deal with stress and inflammatory responses
The Adrenal Cortex is _____ for life and the Adrenal Medulla is _____ for life
Vital
Non-vital
What hormones are produced by the Adrenal Medulla?
Epinephrine and norepinephrine
What does the Adrenal Medulla directly interact with and add do?
Extends effects of the autonomic nervous system “fight or flight”
Where is the Pancreas located?
Below the stomach in the curve of the duodenum
The Pancreas has both _______ and _________ functions
Endocrine AND Exocrine
How does the Pancreas function as an exocrine gland?
Produces digestive enzymes
How does the Pancreas function as an endocrine gland?
Beta cells produce insulin
Alpha cells produce glucagon
What is insulin? How does it work?
A HYPOglycemic hormone (LOWERS blood glucose levels)
Increase glucose reuptake in cells and storage of fats, aminos, and glucose
When do insulin levels increase?
After eating
What is glucagon? How does it work?
A HYPERglycemic hormone (INCREASES blood glucose levels)
Causes liver to break down glycogen (stored glucose) and promotes the breakdown of fat and protein
When do glucagon levels increase?
During fasting
What hormone does the Pineal Gland produce? What is its purpose?
Melatonin
Sleep, circadian and circannual rhythm, puberty
What hormone does the Thymus produce? What is its purpose?
Thymosin (T-cells)
“Programs” T-lymphocytes for immune system
What hormone does the Testes produce? What is its purpose?
Testosterone
Secondary male characteristics
What hormone does the Ovaries produce? What is its purpose?
Estrogen and Progesterone
Menstrual cycle and secondary female characteristics
Also maintains pregnancy
Describe Gigantism:
Which gland?
What causes it?
Symptoms?
Risk group?
Pituitary Gland disorder
Overproduction of GH (growth hormone), usually due to a tumor on the pituitary
AKA acromegaly in adulthood
Prominent jaw, large hands and feet, thick facial features, and delayed puberty
Describe Dwarfism:
Which gland?
What causes it?
Symptoms?
Risk group?
Pituitary Gland disorder
Underproduction of GH (growth hormone)
Slow growth rate
Describe Goiter:
Which gland?
What causes it?
Symptoms?
Risk group?
Thyroid Gland disorder
Decreased secretion of T3/T4 so Thyroid Gland grows larger to make up for lack of hormones
Can happen if you severely lack IODINE, 40+, women, smokers
Describe Graves’ Disease:
Which gland?
What causes it?
Symptoms?
Risk group?
Thyroid Gland disorder
Autoimmune, antibodies mimic effect of TSH (thyroid secretion hormone) so over secretion of T3/T4 from Thyroid Gland
Causes increased metabolism, weight loss, rapid heartbeat, sweating, anxiety, and protruding eyes
More likely in women, middle aged, history of autoimmune disease
Describe Congenital Hypothyroidism (Cretinism):
Which gland?
What causes it?
Symptoms?
Risk group?
Thyroid Gland disorder
Underdeveloped Thyroid Gland causes underproduction of T3/T4 hormones
Cause intellectual disability, disproportionate body, thick tongue and neck
Genetic, can occur if not enough iodine in pregnancy
Describe Cushing’s Disease:
Which gland?
What causes it?
Symptoms?
Risk group?
Adrenal Gland disorder
Over secretion of cortisol, sometimes caused by pituitary tumor sending too much ACTH or steroid medications
Causes moon face, hump on upper back, facial hair, and easy bruising
More likely in women, middle aged, or if have hereditary pituitary tumors
Describe Diabetes Mellitus:
Which gland?
What causes it?
Symptoms?
Risk group?
Pancreas Gland disorder
Type 1: insulin not secreted, usually children
Type 2: insulin present but ineffective, usually adults, obesity, family history
Causes hyperglycemia (too much glucose in blood), leading to polydipsia (excessive thirst), polyuria, lethargy, polyphagia (excessive eating), stomach issues, and hyperventilation
