Ch 1 A&P Flashcards
Major glands of the Endocrine system
Hypothalamus
Pituitary
Thyroid
Parathyroid
Pancreas
Adrenals
Ovaries & Testes
Pineal Gland
A specific cell with specific receptors that will respond to specific hormones
Target cell
What has receptors that bind and recognize a hormone?
Target cells for that specific hormone
A target cell will have ______ receptors for a particular hormone
2,000-100,000
Hormones are either ____-soluble or _____-soluble
Lipid-soluble
Water-soluble
Lipid Soluble Hormones
- Steroid hormones
- Thyroid hormones
- Nitric Oxide
Water soluble hormone receptors
Amino Acids
- Short-chain: Antidiuretic Hormone
- Long-chain: Insulin
Hormones influence their target cells by:
Chemically binding to specific protein
‘Master SWITCHBOARD’, part of the brain that controls the endocrine system
Hypothalamus
Acts as a major link between the endocrine system and the nervous system
Hypothalamus
‘MASTER GLAND’ of the body because it regulates the activity of the endocrine glands
Pituitary gland
How many hormones does the hypothalamus secrete?
9
How many hormones does the pituitary gland secrete?
7
Stalk like structure, attaches the pituitary to the hypothalamus
Infundibulum
Within the infundibulum, blood vessels that connect capillaries in the hypothalamus to capillaries in the anterior pituitary and carries hormones secreted by the hypothalamus to the anterior pituitary
Hypophyseal portal veins
Gonadotropin-releasing hormones (GnRH) stimulates:
FSH & LH
Growth hormone-releasing hormone stimulates:
HGH & IGF
Growth hormone-inhibiting hormone inhibits
HGH & IGF
Thyroid-releasing hormone stimulates
TSH
Prolactin-releasing hormone stimulates
PR
Prolactin-inhibiting hormone inhibits:
PR
Corticotropin-releasing hormone stimulates:
ACTH
Stimulates FSH & LH
Gonadotropin-releasing hormone
Stimulates HGH & IGF
Growth hormone-releasing hormone
Inhibits HGH & IGF
Growth hormone-inhibiting hormone
Stimulates TSH
Thyroid-releasing hormone
Stimulates PR
Prolactin-releasing hormone
Inhibits PR
Prolactin-inhibiting hormone
Stimulates ACTH
Corticotropin-releasing hormone
Gland that is about the size of a small grape and has two lobes
Pituitary gland
Both lobes of the pituitary rest in the ________, a cup shaped depression in the sphenoid bone
Hypophyseal fossa
A hormone that stimulates an endocrine gland to grow and secrete its hormones
Tropic Hormones
Promotes synthesis and secretion of Insulin-like Growth Factors (IGFs)
Human Growth Hormone (HGH)
From Anterior Pituitary
Insulin-like growth factors are proteins secreted mainly by cells in the liver, but is also secreted in skeletal muscles, cartilage, bones, and other tissues in response to stimulation of:
HGH
Stimulates protein synthesis, helps maintain muscle and bone mass, and promote healing of injury and tissue repair
HGH
Enhances breakdown of triglycerides, which release fatty acid into the blood, and breakdown of liver glycogen, which releases glucose into the blood
HGH
Maintains blood concentration by means of a negative feedback loop
HGH
What hormone controls secretion of HGH when blood glucose is low?
Growth Hormone-Releasing Hormone (GHRH)
What hormone controls secretion of HGH when blood glucose levels are too high?
Growth Hormone-Inhibiting Hormone (GHIH)
Stimulates the synthesis and secretion of thyroid hormones by the thyroid gland
Thyroid-Stimulating Hormone (TSH)
From Anterior Pituitary
What controls Thyroid-Stimulating Hormone (TSH) secretion?
Thyrotropin-Releasing Hormone (TRH) from the Hypothalamus
Initiates the development of ovarian follicles, stimulates follicular cells to excrete estrogen.
Stimulates sperm production in testes.
Follicle-Stimulation Hormone (FSH)
From Anterior Pituitary
What controls FSH secretion?
GnRH from the hypothalamus
Triggers ovulation
Stimulates formation of the corpus luteum in the ovary and the secretion of progesterone by the corpus luteum
Stimulates the testes to secrete testosterone
Luteinizing Hormone (LH)
From Anterior Pituitary
Controls the secretion of LH
GnRH from the hypothalamus
Initiates and maintains milk production by the mammary glands
Prolactin (PRL)
From Anterior Pituitary
Suppresses release of prolactin most of the time
Prolactin-Inhibiting Hormone (PIH)
From Anterior Pituitary
Promote the secretion of Prolactin
Estrogens during pregnancy
Controls the production and secretion of hormones called Glucocorticoids by the cortex (outer portion) of the adrenal gland
Adrenocorticotropic Hormone (ACTH)
From Anterior Pituitary
Stimulates the secretion of Adrenocorticotropic Hormone (ACTH)
Corticotropin-Releasing Hormone from the Hypothalamus
Excessive amount can cause darkening of the skin
Very little in humans
Melanocyte-Stimulating Hormone (MSH)
From Anterior Pituitary
Posterior pituitary contains axons and axon terminals of neurosecretory cells whose cell bodies are in:
The Hypothalamus
The posterior pituitary does not synthesize hormones, but it does store and release which two hormones?
Oxytocin
Antidiuretic Hormone (ADH)
Released in large quantities just prior to childbirth to enhance contraction of smooth muscle cells in the wall of the uterus
Oxytocin
From Posterior Pituitary
Stimulates milk ejection from the mammary glands in response to the suckling infant
Oxytocin
From Posterior Pituitary
Decreases urine production
Causes the kidneys to retain more water, thus decreasing urine volume
Decreases water loss through sweating
Causes constriction of arterioles, thus causing an increase in blood pressure
Antidiuretic Hormone (ADH)
From Posterior Pituitary
In the absence of ADH, an individual’s urine output will increase from 1-2 liters per day to:
20 Liters
The thyroid gland’s function is to run the:
Basal metabolic rate
The rate at which the body uses energy while at rest to keep vital functions going, such as breathing, keeping the heart beating, and keeping the body warm
Basal Metabolic Rate (BMR)
Butterfly shaped gland located just below the larynx
Composed of right and left lobes on either side of the trachea
Thyroid
Thyroid
Spherical sacs that make up most of the gland
Thyroid follicles
Thyroid
The wall of each follicle consists of cells called Follicular cells which produce which two thyroid hormones?
Thyroxine (T4)
Triiodothyronine (T3)
Most body cells have receptors for ______ hormones
Thyroid
Hormones increase BMR, the rate of oxygen consumption under standard or basal conditions
Thyroid homones
Hormones that play an important role in the maintenance of normal body temperature
Thyroid hormones
Stimulate protein synthesis
INCREASES the use of glucose and fatty acid for ATP production
INCREASES the breakdown of triglycerides
ENHANCES cholesterol excretion thus reducing blood cholesterol
Thyroid hormones
Thyroid hormones stimulate growth, particularly the nervous and skeletal systems with _____ and ______
Human Growth Hormone
Insulin
Calcitonin is produced by _______ cells of the thyroid gland
Parafollicular cells
Decreases the level of calcium in the blood by inhibiting the action of osteoclasts, the cells that break down bone
Calcitonin
Small round masses of glandular tissue that are partially embedded in the posterior surface of the thyroid gland
Parathyroid gland
What releases parathyroid hormone (PTH)?
Chief cells (from the parathyroid)
Parathyroid Hormone (PTH) is the major regulator of the levels of which ions in the blood?
Calcium
Magnesium
Phosphate
Increases the number and activity of osteoclasts, which break down bone extracellular matrix and release calcium and phosphate into the blood
Parathyroid Hormone (PTH)
PTH produces which three changes in the kidney?
Slows loss of Ca+ and Mg
Increases loss of Phosphate
Formation of the hormone Calcitriol
Elevated levels of PTH can cause what symptoms?
Bone Pain
Kidney Stones
Headaches
Abdominal Pain
Low levels of PTH can cause what kind of symptoms?
Carpopedal spasms
Abdominal cramps
Muscle cramps
Flattened organ located in the curve of the duodenum, the first part of the small intestine
Has both endocrine and exocrine functions
Pancreas
The endocrine part of the pancreas consists of clusters of cells called:
Pancreatic islets (Islets of Langerhans)
Alpha cells secrete the hormone:
Glucagon
Beta cells secrete the hormone:
Insulin
Alpha cells release is stimulated by the ______ division of the ANS
Sympathetic
Beta cells release is stimulated by the _______ division of the ANS
Parasympathetic
Main action is to increase blood glucose levels when it falls below normal
Glucagon
Helps move glucose into cells, especially muscle fibers, which lower blood glucose level when it is too high
Insulin
Controls secretion of both glucagon and insulin via negative feedback
Blood Glucose
Promotes uptake of amino acids into the body cells and increases the synthesis of protein and fatty acid within the cells
Insulin
The Adrenal cortex consists of which three zones?
Zona Glomerulosa (OUTER)
Zona Fasciculata (MIDDLE)
Zona Reticularis (INNER)
Releases hormones called mineral corticoids because of their effect on mineral homeostasis
Aldosterone
Zona Glomerulosa (Outer zone of the Adrenal Cortex)
Releases hormones called glucocorticoids because they affect glucose homeostasis
Cortisol
Zona Fasciculata (Middle zone of the Adrenal Cortex)
Zone of the Adrenal Cortex that releases androgens
Zona Reticularis (Inner zone of the Adrenal Cortex)
Adrenal Medulla
Consists of _________ cells of the ANS that are specialized to secrete hormones known as catecholamines
- Epinephrine
- Norepinephrine
Postganglionic cells
Major mineral corticoid
Aldosterone
Regulates homeostasis of two mineral ions, Sodium (NA+) and Potassium ions (K+)
- Increases reabsorption of Na+ from urine to blood
- Stimulates excretion of K+ into urine
Aldosterone
Adjusts blood pressure and volume, promotes excretion of H+ in the urine.
Aldosterone
Secretion of aldosterone occurs as part of the ______ pathway
Renin-angiotensin-aldosterone pathway
Conditions that initiate the renin-angiotensin-aldosterone pathway
Change in blood pressure/volume:
- Dehydration
- Na+ deficiency
- Hemorrhage
Lowered blood pressure stimulates the kidney to secrete the enzyme _______, which promotes a reaction in the blood to form angiotensin I
Renin
As blood flows through the lungs, which enzyme converts inactive angiotensin I into active hormone angiotensin II?
Angiotensin converting enzyme (ACE)
Angiotensin II stimulates the adrenal cortex to secrete:
Aldosterone
Aldosterone acts on the kidneys to promote the return of ____ and water to blood, which increases blood pressure (less is loss in urine)
Na+
Most abundant glucocorticoid
Cortisol
Actions of glucocorticoids
Protein breakdown
Triglyceride breakdown
Glucose formation
Anti-inflammatory effects
Depression of immune response
A low blood level of cortisol stimulates neurosecretory cells in the hypothalamus to secrete _______ to the Anterior Pituitary.
This stimulates the release of _________.
______ stimulates cells of the adrenal cortex to secrete cortisol
Corticotropin-releasing hormone (CRH)
Adrenocorticotropic hormone (ACTH)
ACTH
In females, adrenal androgens play what two important roles?
Contribute to libido
Converted into estrogens by other body tissues
After menopause, all female estrogen comes from conversions of:
Adrenal Androgens
Adrenal Medulla
In stressful situation and during exercise, which neurons stimulate the cells of the adrenal medulla to secrete epinephrine and norepinephrine?
Sympathetic preganglionic neurons
Increase blood flow to the heart, liver, skeletal muscle, and adipose tissue; dilate airways to the lungs; and increase blood levels of glucose and fatty acid; also helps the body resist stress
Epinephrine and Norepinephrine
A small endocrine gland attached to the roof of the third ventricle of the brain at the midline
Pineal Gland
Hormone secreted by the pineal gland that contributes to setting the body’s biological clock (circadian rhythm)
Melatonin
Aging
Human growth hormone decreases, this causes:
Muscle Atrophy
Aging
Thyroid hormones (T3, T4, and Calcitonin) decreases causing:
Decreased metabolic rate
Increased body fat
Hypothyroidism
As we age Parathyroid hormone:
Rises
The rise in PTH and the fall in calcitonin as we age results in:
Decrease in bone mass leading to osteoporosis
As we age insulin is released more _____ causing blood glucose levels to increase faster
Slowly
As we age
Estrogen decreases. Ovaries no longer respond to gonadotropins. This leads to conditions like:
Osteoporosis
High blood cholesterol
Atherosclerosis
Any stimulus that produces a stress response
Stressor
First stage of stress response
Fight-or-flight
Second stage of stress response
Resistance reaction
Third stage of stress response
Exhaustion
Flight-or-flight
Initiated by nerve impulses from the ______ to the sympathetic division of the ANS
Hypothalamus
Fight-or-flight response bring huge amounts of glucose and oxygen to:
Brain
Skeletal muscles
Heart
Fight-or-flight response reduces blood flow to where?
This helps preserve blood fluid volume in case of severe bleeding
Kidneys
Helps the body continue fighting a stressor long after the fight-or-flight response dissipates
Resistance Reaction
Stressor stage that uses cortisol, Growth hormone-releasing hormone, and Thyrotropin-releasing Hormone
Resistance Reaction
When the resistance stressor stage fails to combat the stressor
Exhaustion
People under stress are at greater risk for:
Developing chronic disease or dying prematurely
Stress related disorders
Gastritis
Ulcerative colitis
Irritable bowel syndrome
Hypertension
Asthma
Rheumatoid arthritis
Migraines
Anxiety
Depression
