Lecture: Endocrine System Flashcards
Define paracrine communication and the chemical involved
Messaging between cells through paracrines within a single tissue
Define Autocrine communication and the chemical involved
When chemical messages (autocrines) are received by the same cells that sent them
Prostoglandins are examples of what?
Autocrines
__1__ communication occurs when the endocrine system uses chemical messengers called __2__ to relay information between cells via the __3__.
Endocrine Communication
Hormones
Bloodstream
Specific cells that bind and receive hormonal messages
Target cells
How do hormones alter the operations of their target cells?
By altering the quantity or type of enzymes or structural proteins in target cells.
How do hormones alter the target cells themselves? (2)
By altering the biochemical properties or physical structure.
Define synaptic communication
Neurons release a neurotransmitter through a synapse close to target cells with appropriate receptors.
What allows the messages of the nervous system to travel so quickly?
Because action potentials travel through axons, a physical pathway;.
Through what medium does paracrine communication take place?
Extracellular fluid
Through what medium does autocrine communication take place?
Extracellular fluid
Through what medium does direct communication take place?
Gap Junctions
Through what medium does synaptic communication take place?
Across synapses
What are the chemical mediators of direct communication?
Ions, small solutes and lipid soluble materials.
Compared to the endocrine system, commands from the nervous system are __1__ and __2__?
Specific
Short lived
What 4 things do the nervous and endocrine system have in common?
Release chemicals that bind to specific receptors
Share some chemical receptors
Regulated by negative feedback mechanisms
Preserve homeostasis
What are the 5 main processes affected by hormones? (5)
Growth Reproductive capability Cell metabolism and energy balance Fluid and nutrient balance Mobilize body defenses
What are endocrine cells? Where do they release fluids?
Glandular secretory cells that release secretions into extracellular fluid
How are exocrine cells different from endocrine cells?
They release secretions onto epithelial surfaces by way of ducts
What are the 3 classes of hormones?
Amino Acid derivatives
Peptide hormones
Lipid derivatives
What is another word for an amino acid derivative?
Biogenic amines
Amino Acid derivatives are synthesized from the __1__, __2___ and __3__.
Amino acids
Tyrosine
Tryptophan
What hormones are made from tyrosine? (4)
Thyroid hormones
Epinephrine
Norepinephrine
Dopamine
What are Catechelomines?
Epinephrine
Norepinephrine
Dopamine
What is the primary hormone of tryptophan?
Melatonin
What are the 2 types of lipid derived hormones?
Eicosanoids
Steroid hormones
What category of hormone includes prostoglandins, leukotrienes, thromboxines and prostacyclins?
Eicosanoids
Steroid hormones are structurally similar to what?
Cholesterol
Where are hormones typically released?
Areas abundant with capillaries
How long does a circulating hormone remain functional?
Between 2 minutes and 1 hour
When hormones bind to specific receptors they can alter cellular activity in what 3 ways?
genetic activity
rate of protein synthesis
cell membrane permeability
Most peptide hormones are synthesized as ______.
Prohormones
Define pro hormones
Inactive molecules that are converted into active hormones before or after being secreted
What are 2 types of peptide hormones?
Glycoproteins
Short poly-petides / small proteins
A protein molecule to which a hormone can bind strongly
Hormone receptor
Define down-regulation
When the presence of a hormone triggers a decrease in the number of receptors for that hormone
Define up-regulation
When the relative absence of a hormone triggers an increase in the number of receptors for that hormone
Where are the two places hormone receptors are located and what are they called?
On the plasma membrane / extracellular receptors
In the target cells / intracellular receptors
Which hormones require extracellular receptors (2) Why?
Catecholamines
Peptide hormones
They are not lipid soluble.
What is a first messenger?
A hormone that binds to an extracellular receptor
What is a second receptor?
An intermediary molecule that appears during a hormone-receptor interaction
What is amplification? What might it trigger?
The appearance of many secondary receptors during hormone reception.
Receptor cascade
An enzyme complex coupled to a membrane receptor
G protein
What can trigger the opening of calcium ion channels in cell membranes or the release of calcium ions from intracellular compartments?
G protein
What two types of hormones most target intracellular receptors?
Steroid hormones
Thyroid hormones
Which hormones can diffuse across the plasma membrane? What does this allow them to do?
Steroid hormones
Alter the DNA in the nucleus of a cell
How do thyroid hormones cross the plasma membrane?
Through transport mechanisms
Which hormones can affect the DNA of mitochondria? What might it do there?
Thyroid hormones
Alter rate of ATP production
What feedback mechanism controls hormone regulation?
Negative feedback
What 3 types of stimuli can trigger hormone production? (3)
Humoral
Hormonal
Neural
Humoral stimuli affect hormone secretions in what regions of the body? (4)
Heart
Pancreas
Parathyroid Glands
Digestive Tract
What hormone stimulates glucose uptake and usage?
Insulin duh
What region of the body is triggered by neural stimuli?
The hypothalamus
What region provides the highest level of endocrine control?
The hypothalamus
Define humoral stimuli
Changes in the composition of extracellular fluid
The pituitary gland releases __1__ total hormones. __2__ are from the anterior, and __3__ from the posterior.
9
7
2
The hypothalamus is inferior to the __1__ and superior to the __2__.
Thalamus
Pituitary gland
The slender, funnel like structure attached to the hypothalamus
The infundibulum
Alternate name for the pituitary gland
Hypophysis
The pituitary gland is nestled in the __1__, a depression in the __2__.
Sella turcica
Sphenoid Bone
What is the function of the seller diaphragm?
To encircle the infundibulum, holding the pituitary in place.
The __1__ isolates the pituitary gland from the __2__.
Sellar diaphragm
Cranial cavity
What organ regulates the functions of the pituitary gland?
The hypothalamus
What hormones does the posterior pituitary gland release?
ADH
Oxytocin
What are the hormones released by the hypothalamus called? Where and what do they affect?
Regulatory hormones
Secretory functions of the endocrine cells in the anterior pituitary
The hypothalamus exerts direct neural control over the endocrine cells where?
In the adrenal medulla
What happens when the sympathetic nervous system is activated?
The adrenal medulla releases epinephrine and norepinephrine into the bloodstream
What is an alternate name for the anterior pituitary?
The adenohypophysis
What are the 3 regions of the adenohypophysis?
Pars distalis
Pars tuberalis
Pars intermedia
Which part of the anterior pituitary is the largest and most anterior?
Pars distalis
Which part of the anterior pituitary wraps around the posterior pituitary?
Pars intermedia
Name the network of vessels in the pituitary gland
Hypophyseal Portal System
Hormones of the anterior pituitary that “turn on” endocrine cells in other organs
Tropic hormones
“Thyroid Stimulating Hormone”
Adenocorticotropic hormone
Follicle stimulating hormone (FSH) and luteinizing hormone (LH) are examples of what?
Gonadotropin hormones
What 6 hormones are produced by the pars distalis?
Adenocorticotropic Hormone Thyroid stimulating hormone FSH LH Prolactin Growth hormone
Alternate name for adenocorticotropic hormone?
Cortico hormone
Alternate name for growth hormone?
Somatotropin
Alternate name for Thyroid stimulating hormone?
Thyrotropin
Adenocortico hormones trigger release of __1__ in the __2__, producing __3__.
Steroid hormones
Adrenal cortex
Glucocorticoids
What does FSH stimulate in women? (2)
Growth of (ovarian) follicles In combination with LH, Estradiol
What does FSH stimulate in men?
Nurse cells
What does LH stimulate in women? (2)
Ovulation
The production of progesterone
What does LH stimulate in men?
Androgen production by intersistial endocrine cells
What is hypogonadism and what is its outcome?
A lack of gonadotropins inhibit the production of sperm or oocytes
What is the function of prolactin (PRL)?
Stimulate mammary gland growth in women.
What neurotransmitter inhibits PRL?
Dopamine
What are somatomedins and what do they do?
Growth factors produced by the liver that stimulate the uptake of amino acids by skeletal muscles and chondrocytes for protein synthesis.
What is the affect of GH on epithelial and connective tissue cells?
Stem cells divide and produce daughter cells
What is the affect of GH on adipose tissue? Make sure to include the specific name for this process.
Triggers the “glucose sparing affect”,
by breaking stored triglycerides into fatty acids that enter the blood stream to generate ATP
What is the affect of GH on the liver?
Breakdown of glycogen stores (associated with diabetogenic affect)
What stimulates the release of melanocyte stimulation hormone?
Pars intermedia
What is caused by melanocyte stimulation hormone?
Localized skin pigmentation, but mostly not in people
For whom is melanocyte stimulation hormone most active? (3)
Young children
Pregnant women
Diseased people
Alternate name for the posterior pituitary gland
Neurohypophysis
The posterior pituitary gland contains __1__ of the neurons of the __2__ and the __3__ nuclei.
Axons
Supra optic
Paraventricular
The neurohypophysis does NOT have
A portal system
The second messenger of OXT and ADH
cAMP
Alternate name for ADH
Vasopressin
What does OXT stimulate in women? (2)
- Contractions of the myometrium during labor
2. Ejection of milk
A consequence of inadequate ADH release
Diabetes insipidus
Connects the two lobes of the thyroid gland
Isthmus
The thyroid gland contains large numbers of __1__ which are shaped like __2__ and lined with __3__ epithelium.
- Thyroid follicles
- Hollow spheres
- Simple cuboidal
Endocrine cells of the thyroid
C (clear) cells or follicular cells
Functions of Epinephrine and norepinephrine?
They are the flight/fight hormones that are released when the body is under extreme stress
What hormones are secreted by the thyroid + abbreviations? (2)
- thyroxine (t4)
2. triiodothyronine (t3)
What is Thyrotoxicosis and what is a symptom?
- Excess thyroid hormone in the body
2. bulging eyes
What is goiter?
Enlargement of the thyroid gland
What causes goiter?
Iodine deficiency
Hormones of the suprarenal or adrenal glands? (2)
- Epinepherine
2. Norepinepherine
What is cortisol (type and class) and what produces it?
Cortisol is a steroid hormone in the glucocorticoid class of hormones
it is produced by the adrenal cortex.
What is the function of cortisol? (6)
Cortisol can help control:
- blood sugar levels
- regulatemetabolism
- reduce inflammation,
- assist with memory formulation.
- It has a controlling effect on salt and water balance
- helps control blood pressure
What produces glucagon (be specific)
alpha cells of the pancreas
What organ produces insulin?
the pancreas
What produces aldosterone?
the zona glomerulosa of the adrenal cortex in the adrenal gland
What produces hormones but are not considered endocrine glands? (2)
- Heart
2. Intestines
Where does ADH do its jobs?
Distal Convoluted Tubule of the kidney
What is albinism a symptom of?
Lack of MSH (melanocyte stimulating hormone)
The hypothalamus is a part of what two systems?
The nervous system and the endocrine system
