Endocrinology Flashcards
What is Endocrinology?
- The study of Hormones that control many different metabolic processes of the body
Definition of Hormone
- chemical messengers secreted by glands into extracellular fluid carried via the blood to target organs.
Hormones target _______ of the body, their effects are ____________.
- target most all cells of the body
- their effects are widespread
What works togther with the endocrine system?
- The Nervous system; the nervous system coordinates with the endocrine system
- The nervous system sends out signals to glands causing them to secrete hormone
Definition of Target organ
- A specific organ a hormone works on
What are the qualities of endocrine glands?
- Ductless
- Produce hormones
- Highly vascularized
What organs are considered true endocrine glands?
- Pituitary gland
- Thyroid
- Parathyroid
- Adreanal glands
- Pineal gland
What organs secrete hormone but are not considered true endocrine organs?
- Hypothalamus
- Gonads
- Placenta
- Pancreas
How far do hormones travel? How do hormones travel to their target organs?
- Hormones travel long distances in the blood or lymph
What types of hormones do not ravel long distances?
- Autocrines
- Paracrines
What is an Autocrine? what is an example of an autocrine?
- A chemical (hormone) that has an effect on the cell that produces it.
- Example; cancer cells
What is a Paracrine? What is an example of a paracrine?
- A paracrine is a locally acting chemical (hormone) that effect cells other than those that secrete the
- Example; Neurons secreting neurotransmitters
True endocrine glands….
- true endocrine glands only purpose is to make and secrete hormone
What are the chemical classifications of hormones?
- Amino acid based
- Steroids
Amino acid based hormones include…
- Amines
- thyroxine
- peptides
- proteins
Steroid hormones
- Are synthesized from cholesterol
- Gonadal and adrenocortical hormones are steroids
Hormones will influence cells that have ________ for it; _________
- Receptors
- Target cells
Hormones act as molecular ______that activate the target cell to respond.
- Messengers
The activation of a target cell by a hormone depends on 3 things
- Blood level of hormone
- Relative number of receptors on or in the target cell
- Bonding affinity between the hormone and target cell
Can the number of recptors on/in target cells change? How?
- Yes
- Hormones influence the number of their receptors on or in a cell
Up-regulation
- Target cells form more receptors in response to a hormone
Down-Regulation
- Target cells decrease/reduce receptors in response to a hormone
What are the ways a hormone can change a target cell?
- Change plasma membrane permeability or potential
- stimulate synthesis of regulatory enzymes/proteins
- Activates/Deactivates enzymes
- Induces secretory activity
- Stimulates mitosis
Specific ______ have specific _______.
- Hormones
- Receptors
The amount of receptors on a cell change __________.
- upon necessity
Hormones alter the rate at which _______.
- The cell creates proteins
Where do peptide hormones bind?
- on receptors on the outside of a cell causing a chemical reaction that triggers responses in cells
Where do steriod hormones bind?
- To receptors on the inside of a cell
how do steriod hormones work?
- Steroid hormone diffuses through the plasma membrane and binds with an intracellular receptor
- The receptor-hormone complex enters the nucleus
- The receptor-hormone complex binds to a specific DNA region
- Binding causes transcription of the gene to mRNA
- mRNA directs protein synthesis
How do peptide hormones work?
- Hormone binds to receptor on the outside of the cell (Hormone is the first messenger)
- Receptor activates G protein
- G protein activates Adenylate cyclase
- Adenylate cyclase converts ATP to cAMP (cAMP is the second messenger)
- cAMP activates protein Kinases
What are they different ways endocrine glands can be stimulated to release hormones?
- Humoral stimuli
- Neural Stimuli
- Hormonal stimuli
What is humoral stimuli? what is an example of it?
- When an endocrine gland secretes a hormone in response to changing levels of ions or nutrients in the blood to keep homeostasis
- Glucagon release by pancreatic alpha cells in response to low blood glucose
What is neural stimuli? What is an example of it?
- Neurons stimulate hormone release
- Contracting of smooth muscle in breast (expelling milk) in response to oxytocin which is stimulated by suckling.
Hormones have profound effects at _________.
- Low concentrations
Hormones circulate in the blood _______ or ________.
- Free
- Bound
Concentrations of hormones in the blood at any given time depends on:
- its rate of release
- speed at which it is inactivated or removed from the body (kidneys and liver)
- Half-life; The time ot takes to decrease the concentration of a given hormone by Half
How long does it take to see the effect of hormones?
- Seconds to Days
Duration of hormone action ranges from _______ to ________ depending on_______
- 10 seconds
- several hours
- depending on the hormone
another name for the pituitary gland
Hypophysis
The Posterior gland has how many lobes? What are their names?
- 2 lobes
- Posterior
- Anterior
Posterior lobe of Pituitary
- Releases neurohormones, hormones that are made by neurons
- It is not a true endocrine gland
Does the posterior pituitary make hormones?
- No; the hypothalamus makes hormones which are stored in the axon terminals of neurons in the posterior pituitary where they are released
Anterior lobe of the pituitary
- Made of glandular tissue
- True endocrine gland
- Acts in conjunction with the hypothalamus to release it hormones
How do Anterior pituitary hormones get realesed?
- Hypothalamic neurons secrete releasing or inhibiting hormones into primary capillary plexus
- Hypothalamic hormones travel through portal veins to anterior pituitary where they trigger the inhibition or release of certain hormones made in the anterior pituitary
- The glandular tissue in the anterior pituitary secretes hormones into the secondary capillary plexus in response to hypothalamic hormones
- The hormones then enter general circulation
The adrenal medulla secretes ________ based hormones called _______ also known as _________ and ___________
- Amino acid based hormones
- Catecholamines
- Epinephrine
- Norepinephrine
Hormones involved in short term stress
- Epinephrine
- Norepinephrine
How short term stress works
- Hypothalamus—–> Spinal cord —–> Adrenal Medulla ——> catecholamines
Effects of short term stress
- Heart rate increases
- Blood pressure increases
- Bronchioles dialate
- Liver converts glycogen to glucose and releases glucose into the blood
- Blood flow changes; reducing digestive system activity and urine output
- Metabolic rate increases
Hormones involved in Long Term stress
- Adrenocorticotropic hormone
- Mineralocorticoids
- Glucocorticoids
How Long term stress works
- Hypothalamus —-> Anterior pituitary (corticotropic cells)—–> Adrenal cortex
- Corticotropic cells secrete adrenocorticotropic hormone
- Adrenocorticotropic hormone’s target is the adrenal cortex
- Adrenal cortex releases steroid based hormones; mineralocorticoids and glucocorticoids
The adrenal cortex secretes _______ based hormones.
- Steroid based
Effects of Long term stress
- Kidneys retain sodium and water
- Blood volume and blood pressure rise
- Proteins and fats converted to glucose or broken down for energy
- Blood glucose increases
- Immune system surpressed
What is another name for epinephrine?
- Adrenaline
Stress stimulates the ________.
- Hypothalamus
Tropic, Trophin, Trophic =
- Affinity/Attraction
Alpha cells of pancreas
- produce glucagon
Beta cells of the pancreas
- Produce insulin
The effects of glucagon and insulin are __________.
- Antagonistic
What is normal blood glucose?
- 90/100 mgs per mL of blood
__________ allows glucose to pass through cells.
- Insulin
Dibetes Mellitus results when there is _______ or ________ of __________.
- Hyposecretion
- Hypoactivity
- Insulin
Type I diabetes results from ________ of insulin.
- Hyposecretion
Type II diabetes results from ________ of insulin.
- Hypoactivity
Hyposecretion of insulin
- not enogh insulin is being made to lower blood glucose
Hypoactivity of insulin
- Insulin resistance; beta cells are secreting insulin but the cells have become resistant to insulin resulting in hyperglycemia
without glucose cells _______. What happens next?
- Starve
- Body makes more glucose avaliable
Where does all this glucose go?
- stored as glycogen in liver first, then fat, then fat in the body
- leaves body through urine
what will be used as an energy source if cells are unable to utilize glucose for energy?
- Fat
What is the problem with breaking down fats for energy?
- Fats and metabolites combine to make ketone bodies (acetocetic acid, acetone, etc.)
- Ketones are acidic
- The building up of ketones in the body changes blood pH lowering it (acidifying)
- when the body is overwhelmed with ketones they overflow into the urine
- Too many ketones in the body can lead to ketoacidosis
A metabolite is a ______ .
Side product
Ketons are mostly ________ made by ________.
- Acids
- made by breaking down fat
Polydipsia
- Many drinks
Polyuria
- Urinate many times
when it comes to diabetes, polyuria happens because
- Sugar is leaving through the urine; water follows the glucose by osmosis.
-emia
- Related to the blood
