chapter 18 endocrine system Flashcards
the whole function of the endocrine system
Endocrine cells and tissues produce about 30 different hormones (chemical messengers)
Controls and coordinates body processes
what are the 4 types of intercellular communication
Direct communication
Paracrine communication
Autocrine communication
Endocrine communication
Exchange of ions and molecules between adjacent cells across gap junctions
Occurs between two cells of the same type
Highly specialized and relatively rare
which intercellular communication?
Direct communication
Chemical signals transfer information from cell to cell within a single tissue
which intercellular communication?
Paracrine communication
Messages affect the same cells that secrete them
Chemicals involved are autocrines
Example: prostaglandins secreted by smooth muscle cells cause the same cells to contract
which intercellular communication?
Autocrine communication
Endocrine cells release chemicals (hormones) that are transported in bloodstream
Alters metabolic activities of many organs
which intercellular communication?
Endocrine communication
the endocrine communication has what type of cell and it functions
Target cells
Have receptors needed to bind and “read” hormonal messages
the function of hormones
Change types, quantities, or activities of enzymes and structural proteins in target cells
Can alter metabolic activities of multiple tissues and organs at the same time
Affect long-term processes like growth and development
the function of the synaptic communication
Neurons release neurotransmitters at a synapse
Leads to action potentials that are propagated along axons
Allows for high-speed “messages” to reach specific destinations
Ideal for crisis management
Both endocrine and nervous systems do?
Rely on release of chemicals that bind to specific receptors on target cells
Share many chemical messengers (e.g., norepinephrine and epinephrine)
Are regulated mainly by negative feedback
Function to preserve homeostasis by coordinating and regulating activities
the endocrine system what do they produce and where is it release?
that produce hormones or paracrines
Endocrine cells release secretions into extracellular fluid
Endocrine organs are scattered throughout body
what are the 3 types of hormones
Amino acid derivatives
Peptide hormones
Lipid derivatives
amino acid derivates also means
biogenic amines
what are examples of Peptide Hormones, types of protein
Glycoproteins
Proteins more than 200 amino acids long that have carbohydrate side chains (e.g., TSH, LH, FSH)
how do hormones travel
Hormones may circulate freely or travel bound to special carrier proteins
Free hormones remain functional for less than an hour and are inactivated when they
Diffuse out of bloodstream and bind to receptors on target cells,
Are absorbed and broken down by liver or kidneys, or
Are broken down by enzymes in blood or interstitial fluids
what are the effects of binding hormones
Alter genetic activity
Alter rate of protein synthesis
Change membrane permeability
receptors absence determines what?
receptor determines hormonal sensitivity of a cell
what are the 2 types of regulation
Down-regulation = Presence of a hormone triggers a decrease in the number of hormone receptors
Up-regulation= Absence of a hormone triggers an increase in the number of hormone receptors
which hormones are able to pass through membranes
Steroid and thyroid hormones
Lipid soluble
intracellular receptors
Catecholamines and peptide hormones
Not lipid soluble
Unable to penetrate plasma membrane
Bind to receptor proteins on outer surface of plasma membrane (extracellular receptors)
what does each messenger do ?
First messenger
Hormone that binds to extracellular receptor
Promotes release of second messenger in cell
Second messenger
Intermediary molecule that appears due to hormone–receptor interaction
May act as enzyme activator, inhibitor, or cofactor
Results in change in rates of metabolic reactions
what are the affects of G proteins and CAMp levels
increasing cAMP level, which accelerates metabolic activity of cell
increase in cAMP level is usually short-lived
Steroid hormones
can alter rate of DNA transcription in nucleus
Alterations in synthesis of enzymes or structural proteins
Directly affect activity and structure of target cell
Thyroid hormones
bind to receptors within nucleus and on mitochondria
Activate genes or change rate of transcription
Increase rates of ATP production
hormones can be triggered by
Humoral stimuli (change in composition of extracellular fluid),
Hormonal stimuli (arrival or removal of hormone),
Neural stimuli (neurotransmitters at neuroglandular junctions)
what organ produces ADH anOXT?
the hypothalamus
what release ADH and OXT
the Pituitary gland posterior lobe
the endocrine system what does it include and what does it produces?
what cells and what do they release into what fluid?
are the endocrine organ scrattered throughout the body?
includes all endocrine cells and tissues that produce
hormones or paracrines
– Endocrine cells release secretions into extracellular fluid
* Unlike exocrine cells
– YES, Endocrine organs are scattered throughout body
what is type 1 diabetes what is it low on?
what doe patients need?
whats the percent of cases and who is mostly developed by it?
Characterized by inadequate insulin production by pancreatic beta cells
– Patients require daily injections or continuous infusion of insulin
– Approximately 5 percent of cases
– Usually develops in children and young adults
type 2 diabetes
– Usually, normal amounts of insulin are produced, at least initially
- Tissues do not respond properly (insulin resistance) – Associated with obesity
- Weight loss can be an effective treatment
Complications of untreated or poorly managed diabetes mellitus include
Kidney degeneration
– Retinal damage (diabetic retinopathy)
* May lead to blindness
– Early heart attacks (3–5 times more likely)
– Peripheral nerve problems (diabetic neuropathies)
– Peripheral tissue damage due to reduced blood flow
- Tissue death, ulceration, infection, and amputation
the hypothalamus regulates what?
sysnthesizes what hormones and where do they transport?
what hormones do they release in the anterior pituitary gland?
contains what center? direct control over what?
Regulates functions of the pituitary gland
– Synthesizes ADH and OXT and transports them to posterior pituitary gland for release
– Secretes regulatory hormones that control secretory activity of anterior pituitary gland
– Contains autonomic centers that exert direct control over adrenal medulla
what are the major endocrine glands
pituitary gland anterior lobe - ACTH,TSH, LSH, GH, FSH, PRL, MSH
posterior lobe - ADH and OXT
Pineal Gland- melatonin
parathyroid Gland- PTH located posterior to thyroid gland
thyroid gland - Thyroxine T4, Triiodothyronine T3, Calcitonin CT
Adrenal Gland - Medulla= Epinephrine, Norepinephrine
Cortex= Cortisol, Corticosterone, Cortisone, Aldosterone, androgens
the pituitary gland lies within?
which diaphragm isolates?
where does is hang? what does it connect by?
what does it release? binds to what?
use what as second messenger?
Lies within sella turcica
Sellar diaphragm isolates pituitary gland from cranial cavity
Hangs inferior to hypothalamus
Connected by infundibulum
Releases nine important peptide hormones
Bind to extracellular receptors
Use cAMP as second messenger
Adrenal Glands lies along where ?
what portion of the adrenal stores fat, steroid hormones?
inner medulla controlled by what division? what do they produce at the end?
Lie along superior border of each kidney
Superficial adrenal cortex
Stores lipids, especially cholesterol and fatty acids
Manufactures steroid hormones (corticosteroids)
Inner adrenal medulla
Secretory activities controlled by sympathetic division of ANS
Produces epinephrine and norepinephrine (catecholamines)
Two classes of hypothalamic regulatory hormones
Releasing hormones (RH)
Stimulate synthesis and secretion of one or more hormones at anterior lobe
Inhibiting hormones (IH)
Prevent synthesis and secretion of hormones from anterior lobe
Rate of secretion is controlled by negative feedback
Pancreas where does it lies between?
what does it contain which cells?
Large gland
Lies in loop between inferior border of stomach and proximal portion of small intestine
Mostly retroperitoneal
Contains exocrine and endocrine cells
