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