Chapter 9 Flashcards
Fast control system
Nervous system
Slow control system
Endocrine system
Hormones control
1.Reproduction
2.Growth and development
3.Mobilization of body defenses
4. Maintenance of homeostasis
5. Regulation of metabolism
Cells secrete hormones into
Extracellular fluids
How do hormones move?
Through blood to target sites
Endocrinology
Study of hormones and endocrine organs
Types of hormones
1.Aminoacid based
2.Steroids
3.Prostaglandins
Types of aminoacids based hormones
Proteins
Peptides
Amines
What are steroids made from?
Cholesterol
What are prostaglandins made from?
Highly active lipids that act as local hormones
What do target cells need to be receptive to hormones?
Specific Protein receptors
How does hormone binding affect the cell?
Hormone binding affects cellular activity
Common hormone actions
- Plasma membrane permeability
- Activating or deactivating enzymes
- Starting or stopping cell division
- Promoting or inhibiting secretion of a product
- Turn transcription on or off
Action mechanisms of hormones
- Direct gene activation
- Second messenger system
Direct gene activation used by
Steroid hormones and thyroid hormones
Second messenger system used by
Protein and peptide hormones
Pathway of direct gene activation
- Steroids go through plasma membrane of their target
- Hormone enters nucleus
3.Hormone binds to receptor
- Hormone-receptor complex binds to sites on cell DNA
- Certain genes activate and transcribe messenger RNA
- New proteins are synthesized
Second messenger system pathway
- Hormone (first messenger) binds to a membrane receptor
- Activated receptor sets off series that activates an enzyme
- Enzyme catalyzes a reaction that produces cAMP (second messenger molecule)
- Oversees additional intracellular changes to promote a specific response in the target cell
Which feedback mechanism maintains hormone levels ?
Negative feedback mechanism
What triggers the release of more hormone?
Stimulus or abnormal low hormone level in blood
When does hormone release stop?
Once an appropriate level in the blood is reached
3 Categories of stimuli that activate endocrine glands
Hormonal
Humoral
Neural
Hormonal stimuli
1.Most common category of stimulus
2.works by:
Endocrine organs activated by other hormones
Example of hormonal stimuli
hormones of hypothalamus stimulate anterior pituitary to secrete it’s hormones
Humoral stimuli
Changing blood levels of certain substances promote hormone release
Humoral
Various body fluids, including blood and bile
“Parathyroid hormone and calcitonin produced in response to changing levels of blood calcium levels “ example of which hormone release system?
Humoral
“Insulin produced in response to changing blood glucose levels” is an example of which hormone release system
Humoral stimuli
Neural stimuli
1.Nerve fibers cause hormone release
- Controlled by sympathetic nervous system
“Sympathetic stimulation of the adrenal medulla to release epinephrine and norepinephrine” is an example of
Neural stimuli hormone release system
Epinephrine and norepinephrine
Adrenaline and non-adrenaline
Which glands have purely endocrine functions?
1.Anterior pituitary
2.Thyroid
3.adrenals
4. Parathyroids
Which glands are ductless glands?
Endocrine
Hormones are released directly into
Blood or lymph
Which glands are mixed glands ? (endocrine and exocrine functions)
Pancreas and gonads
Which is the master endocrine gland?
Pituitary gland
Anterior pituitary made of
Glandular tissue
Posterior pituitary made of
Nervous tissue
Which bone houses the pituitary gland?
Sphenoid bone specifically: sella turcica
Pea sized gland that hangs by a stalk from the hypothalamus
Pituitary gland
What kind of hormones does hypothalamus make?
Releasing hormones
Inhibiting hormones
Examples of 2 hormones made by hypothalamus
Oxytocin
Antidiuretic hormone
Releasing and inhibiting hormones are released into
Portal circulation which connects hypothalamus to anterior pituitary
Oxytocin and antidiuretic hormone are carried to
Posterior pituitary via neurosecretory cells for storage
Posterior pituitary
DOES NOT MAKE HORMONES, stores them & releases them
Releases oxytocin and ADH
Oxytocin
Contractions of uterus
Sexual relations
Breastfeeding
What causes the let-down reflex
Milk ejection
Caused by oxytocin
ADH (antidiuretic hormone)
- Inhibits urine production/ Promotes water reabsorption by kidneys
What happens when urine volume decreases ?
Blood pressure increases
Why is ADH aka vasopressin?
Makes arterioles constrict, leading to increased BP. Only in large amounts
What inhibits ADH secretion?
Alcohol
Why is inhibiting ADH secretion bad
Pee a lot
Can cause dehydration
Which hormones have nonendocrine targets?
Growth hormone
Prolactin
Which are tropic hormones?
1.Follicle-stimulating hormones
2. Luteinizing hormone
3.Thyrotropic hormone
4.Adrenocorticotropic hormone
Which are the six anterior pituitary hormones?
- Growth hormone
- Prolactin
- Follicle-stimulating hormone
4.Luteinizing hormone - Thyrotropic hormone
- Adrenocorticotropic hormone
Tropic hormones
Target other endocrine glands
4 characteristics of all anterior pituitary hormones
- Are proteins/peptides
- Act through second-messenger systems
- Regulated by hormonal stimuli
- Regulated mostly by negative feedback
Which is the general metabolic hormone?
Growth hormone
Growth hormone responsible for
- Growth of skeletal muscles and long bones
- Determines final body size
3.amino acids built into proteins - Fats broken down for energy
Prolactin (PRL)
Stimulate & maintain milk production in women
Unknown role in men
Gonadotropic hormones
Follicle stimulating hormone (FSH)
Lutenizing hormone (LH)
FSH
Follicle development in ovaries
Sperm development in testes
LH
Lutenizing hormone
1. Ovulation in females
2. Testosterone production in males
Thyrotropic hormone aka thyroid stimulating hormone TH or TSH
Growth and activity of thyroid gland
Adrenocorticotropic hormone ACTH
Regulates endocrine activity of the adrenal cortex
Pineal gland location
Roof of third ventricle of brain
Pineal gland
1.secretes melatonin.
Sleep wake cycle
- Coordinates fertility hormones in humans. Inhibits reproductive system until mature
Thyroid gland location
Base of throat,
Inferior to Adam’s apple
Parts of thyroid gland
Two lobes and connecting isthmus
Follicles
Follicles
Hollow structures that store colloidal material
Thyroid gland produces 2 hormones which are
Thyroid hormone
Calcitonin
Thyroid cartilage is commonly known as
Adam’s apple
Which is the major metabolic hormone?
Thyroid hormone
Function of thyroid hormone
Controls rate of oxidation of glucose to supply body heat and chemical energy
Which hormone is needed for tissue growth and development?
Thyroid hormone
Which are the components of thyroid hormone?
1.Triiodothyronine (T3)- conversion of T4 at target tissues
Thyroxine (T4)- secreted by thyroid follicles
Iodine containing hormones
Thyroxine
Triiodothyronine
Which cells are responsible for producing the thyroid hormones?
Follicular cells
Calcitonin
Decreases blood calcium levels by causing calcium deposition on bone
Which is the antagonist to the parathyroid hormone?
Calcitonin
Calcitonin is produced by?
Parafollicular cells found between follicles
Parathyroid glands location
Tiny masses on posterior face of thyroid
Secrete parathyroid hormone
Function of PTH
1.Most important regulator of Ca2+ homeostasis
- Stimulates osteoclasts, removes calcium from bone
- Stimulates kidneys and intestine to absorb more calcium
Which is the hypercalcemic hormone?
PTH
Increases blood calcium levels
Thymus location
Located in upper thorax, posterior to sternum
Who has the largest thymus?
Infants and children
Decreases in size throughout adulthood
Thymus function
Makes thymosin
Thymosin function
Matures some types of white blood cells
Develops immune system
Adrenal glands location
Sit on top of kidneys
Regions of adrenal glands
Adrenal cortex
Adrenal medulla
Adrenal cortex layers: outermost
Secretes Mineralocorticoids
Adrenal cortex layers: middle
Glucorticoids
Adrenal cortex layers: innermost
Sex hormones
Adrenal cortex function
Has 3 layers that make corticosteroids
Adrenal medulla
Inner neural tissue region
Makes epinephrine and norepinephrine
Mineralocorticoids (mainly aldosterone)
1.Mineral (salt) content in blood, particularly sodium and potassium ions
- Water and electrolyte balance
- Target organ is kidney
What stimulates the release of aldosterone?
- Humoral factors (fewer sodium or too many potassium ions in blood)
- Hormonal stimulation (ACTH)
- Renin and angiotensin II in response to a drop of blood pressure
What inhibits aldosterone production?
Atrial natriuretic peptide (ANP), hormone produced by the heart when BP is too high
Glucocorticoids function
1.Promote normal cell metabolism
2.Help resist long term stressors by raising glucose levels (hyperglycemic hormone)
- Anti-inflammatory properties
- Released in response to increased blood levels of ACTH
Cortisone and cortisol are types of
Glucocorticoids
Which is the hyperglycemic hormone
Glucocorticoids
What is released in response to increased blood levels of ACTH ?
Glucocorticoids
Small amounts of ___ hormones are made throughout life
Sex hormones
Most of the sex hormones produced are
Androgens (male sex hormones), but some estrogens are produced as well
Catecholamines produced by adrenal medulla
Epinephrine and norepinephrine
Effect on epinephrine and norepinephrine on body
1.Increase heart rate
2.increasw BP
3. Increases Blood glucose
4. Dilated small passageways of lungs
Pancreas location
Abdomen, close to stomach
Pancreas has both___ & ____ functions
Endocrine and exocrine functions
Mixed gland
Islets of langerhans
Pancreatic islets
Make hormones:
1.Insulin
2.Glucagon
Hormones are antagonists that maintain blood sugar homeostasis
What produces insulin?
Beta cells of islets of langerhans
Glucagon produced by
Alpha cells of islets of langerhans
Antagonists that maintain blood sugar homeostasis
- Insulin
- Glucagon
Function of exocrine cells of pancreas
Reduce enzymes of digestion and bicarbonate
Glucagon
Increases Blood glucose levels (Alpha)
Insulin
Decreases blood glucose levels
What increases the rate of glucose uptake and metabolism (hypoglycemic)
Insulin
What is released when blood glucose levels are low?
Glucagon
How does glucagon function
Stimulates liver to release glucose to blood, thus increasing blood glucose levels
Normal blood glucose levels
90mg/100 ml
Gonads make
Sex cells and sex hormones
Location of ovaries
Pelvic cavity
Function of ovaries
Make eggs
Groups of steroid hormones produced by ovaries
Estrogens
Progesterone
Testes
1.Male gonads suspended outside of pelvic cavity
2. Make sperm and androgens like testosterone
- 3 degrees lower than body temperature
Estrogens
1.Development of secondary female characteristics, widening of hips
- Mature female reproductive organs
With progesterone, estrogens also
1.Promote breast development
- Regulate menstrual cycle
Progesterone function
- Brings menstrual cycle with the help of estrogen
- Helps embryo implant in uterus
- Helps prepare breasts for lactation
Testes function
Make androgens
Testosterone is most important androgen
Testosterone function
- Adult male, secondary sex characteristics: deep voice, hair, muscle
- Growth and maturation of male reproductive system
- Sperm cell production
Other hormone producing tissues and hormones
Non endocrine
1. Stomach
2. Small intestine
3.Kidneys
4.Heart
Stomach makes
Growin and gastrin
Small intestine makes
Cholecystokinin
cho·le·cys·to·ki·nin
Kidney hormones
erythropoietin
Renin
Heart produces
ANP
Atrial natriuretic peptide
Placenta
Makes hormones that maintain pregnancy
Some hormones part of labor
Relaxin
Relaxes pelvic ligaments and pubic symphysis for childbirth
Human placental lactogen hPL
Prepares breasts for lactation made by placenta
What makes hCG? As well as estrogen, progesterone and other hormones
Placenta hCG=human chorionic gonadotropin
Describe the efficiency of the endocrine system
In the absence of disease, efficiency of endocrine system remains high until old age
Decreased function of female ovaries at menopause leads to symptoms such as
- Osteoporosis,
Increased chance of heart disease and possible mood changes
What happens to the efficiency of the endocrine glands with age?
Efficiency of all endocrine glands decreases with age
Increased risk of diabetes mellitus
Immune system depression
lower metabolic rate
cancer rates in some areas