BIOL 320 EXAM 1 TAMU TAYLOR

What is cheating?

Intentionally using or attempting to use unauthorized materials, information, study aids, or other devices or materials in any academic exercise

What is fabrication?

Making up data or results, and recording or reporting them

What is falsification?

Manipulating research materials, equipment, or processes, or changing or omitting data or results such that the research is not accurately represented in the research record

What is multiple submissions?

Submitting substantial portions of the same work (including oral reports) for credit more than once without authorization from the instructor of the class for which the student submits the work

What is plagiarism?

The appropriation of another person's ideas, processes, results, or words without giving appropriate credit.

What is complicity?

Intentionally or knowingly helping, or attempting to help, another to commit an act of academic misconduct.

What is endocrinology?

Study of hormones and endocrine glands

What is autocrine signaling?

Secreted by cells in a local area, influences the activity of the same cell from which it was secreted.

Example would be eicosanoids or WBCs signaling to itself to replicate

What is paracrine signaling?

Cells will secrete chemical messenger into interstitial fluid and effect other tissue that neighbors the secreting cell.

NOT IN BLOODSTREAM.

For example histamines that stimulate vasodilation in nearby blood vessels

What is neurotransmitter signaling? Between autocrine, paracrine, and endocrine which type of signaling does this fall under?

Chemical messengers secreted by neurons that activate an adjacent cell (neuron, muscle, gland) by traveling across a synaptic cleft.

Technically under paracrine but is also its own division of signaling

What is endocrine signaling?

Cell secretes chemical messenger into bloodstream and influences target tissue with appropriate receptor to hormone

The testes secrete testosterone that act on itself. Is this still an example of endocrine?

YES

The hormone enters the blood stream and travels body wide, even though it may act on itself

What does the cortex of the adrenal glands make?

steroids (cortisol, aldosterone)

What does the medulla of the adrenal glands make?

catecholamines (epinephrine and norepinephrine)

What are the 5 major endocrine glands that have only endocrine function?

Pituitary gland, Pineal gland, Thyroid gland, Parathyroid gland, Adrenal gland

What are some organs containing endocrine cells?

Hypothalamus, Skin, Thymus, Heart, Liver, Stomach, Pancreas, Small intestine, Kidney, Gonads

What are the differences between endocrine and nervous system communication?

In both cases, cells release a chemical that acts on other cells.

Endocrine secretes hormones into bloodstream while nervous system uses neurotransmitters.

Nervous system is much faster than endocrine system (ms vs s).

Nervous system acts very shortly while endocrine system tends to have longer- lasting effects

Are hormones amplitude or frequency modulated?

amplitude modulated, meaning more hormone released and bound to target tissue means stronger response

Are action potentials amplitude or frequency modulated?

frequency modulated, meaning amount of signal each time is same, but more signals leads to a stronger response

What is chronic secretion? Give an example

relatively constant blood levels of hormone over long periods of time (think thyroid hormone)

What is acute secretion? Give an example

hormone concentrations change suddenly and irregularly (think epinephrine)

What is cyclic secretion? Give an example

hormones are secreted at predictable intervals and concentrations (think hormones involved in periods)

Between water and lipid soluble hormones, would each exhibit chronic, acute, or cyclic secretion?

Chronic and cyclic = lipid as it can last longer Acute = water as it has short half life

What is humoral control?

Response to blood levels of some chemical

For example, if blood sugar is below a certain level, then glucagon will be released

What is hormonal control? What terms are common for hormonal control?

A hormone induces the secretion of another hormone (positive and negative feedback)

Usually has "tropin" or "tropic" term = acts on other hormones

What is neural control?

ANS will stimulate release of hormone based on situation

Fight or Flight for example

A neuron releases a neurotransmitter at a synapse to stimulate a hormone's secretion. What kind of control is this?

Neural control

A neuron releases a neuropeptide hormone into the blood, which then stimulates another hormone's secretion. What kind of control is this?

Hormonal control

True or False: Many hormones inhibit the secretion of itself.

True, this is an example of negative feedback

Usually, the hormone's secretion is inhibited by the hormone itself once blood levels have reached a certain point

What three factors influence whether a target cell is influenced by a hormone or not?

Hormone levels in the bloodNumber of receptors on target tissueAffinity of hormone for receptors (does it need low or high concentrations)

What is up-regulation? When is this common?

Hormone binds to receptor, which initiates formation of more receptors so it can bind to more hormone.

Usually occurs if there is too little hormone in bloodstream or may be due to positive feedback loop

What is down regulation? When is this common? How is this related to type II diabetes?

Hormone binds to receptor, which de-sensitizes receptors and less receptors bind to hormone

Usually happens if there is too much hormone in bloodstream Think type 2 diabetes - down-regulation of insulin receptors

What are some actions of hormones? Which events are only excitatory?

1. Alter plasma membrane permeability (open and close ion channels) 2. Stimulate protein synthesis

3. Activate and deactivate enzymes.

Which hormonal events are only excitatory?

Induce secretory activity & Stimulate mitotic activity

What are all steroid hormones derived from?

Cholesterol

Which glands usually produce steroid hormones?

Produced from gonads (testosterone and estrogen) and adrenal cortex (cortisol and aldosterone)

What are biogenic amines?

Derived from amino acids that are modified (catecholamines). Example would be norepinephrine

Are biogentic amines water soluble?

yes except for thyroid hormone

What are the three most common catecholamines?

Dopamine

Norepinephrine

Epinephrine

True or False: Thyroid hormone is rare example of a hormone that looks water soluble but isn't.

True

Thyroid hormone is derived from tyrosine which is aromatic and has some lipophilic nature, allowing it to directly diffuse across membrane

What enzyme breaks down cAMP?

phosphodiesterase (PDE)

Describe the PIP2 signaling mechanism. Which hormones use this mechanism?

Hormone binds and activates G protein

G protein activates phospholipase C enzyme, which splits phospholipids into diacylglycerol (DAG) and IP3 DAG activates protein kinases while IP3 releases Ca2+ Ca2+ can alter enzymes or bind to calmodulin Hormones include oxytocin, ADH, and epinephrine

How do lipid soluble hormones and thyroid hormones act on cells?

Hormone diffuses through membrane and binds to intracellular receptor

Receptor-hormone complex (chaperone complex) enters nucleus and binds to specific sequence of DNA

mRNA directs protein synthesis

What are some ways to administer steroid based hormones?

No injection needed

Ingested, topical cream, etc.

What two factors influence hormone concentration?

The rate of release

The speed of inactivation

Would water soluble or fat soluble hormones have a shorter half life?

Water soluble because the enzymes that digest the hormone are already present in the bloodstream

Also, water soluble hormones usually are involved in amplification as they rely on secondary messengers, so we need to remove them faster so we don't get over-response

What is conjugation? What is it used for?

Conjugation is the process of removing lipid soluble hormones by having specific water soluble molecules to the hormones, marking them for removal

What three ways can we inactivate hormones? What are the primary ways to do so?

EnzymesKidneys and filtration into urine (primary method)

Liver and detoxification of blood (primary method)

What is the difference between synergism and antagonism?

Synergism = hormones work together (leads to amplification)

Antagonism = hormone causes opposite effect of other

What is a permissive hormone?

A hormone allows the action of another hormone

What is a chylomicron?

Hormone protein unit

What is another name for the pituitary gland?

Hypophysis

What connects the pituitary gland to the hypothalamus?

Infundibulum

What is the precursor for the anterior pituitary gland? How does this influence the nature of secretion?

hypophyseal pouch from part of oral cavity called pituitary diverticulum (hormonal secretion in nature)

What is the precursor for the posterior pituitary gland? How does this influence the nature of secretion?

continuous with hypothalamus, neurohypophyseal bud from gray matter (neural secretion in nature)

What part of the pituitary secretes neuropeptides?

Posterior

What part of the pituitary secretes traditional hormones?

Anterior

What is the pathway of secretion of the anterior pituitary?

Neurons in ventral hypothalamus secrete hormone into primary capillary plexus

Hormone travels through hypophyseal portal system (bloodstream)

Hormones reach anterior pituitary, which stimulate specific cells of the anterior pituitary to release or inhibit hormones

Anterior pituitary hormones are secreted into secondary capillary plexus

What is the pathway of secretion of the posterior pituitary?

Neurons in paraventricular or supraoptic nuclei in hypothalamus induce action potential which carries neurohormones along hypothalamic-hypophyseal tract

AP travels along axons and reaches axon terminals in posterior pituitary, where hormone is stored in axon terminals until needed to be released

What two nuclei in the hypothalamus are important in this pathway?

paraventricular or supraoptic nuclei

What is another name for the anterior pituitary?

Adenohypophysis

What is another name for the posterior pituitary?

Neurohypophysis

What path carries hormones to the anterior pituitary?

Hypothalamohypophyseal portal system

What path carries hormones to the posterior pituitary?

Hypothalamohypophyseal tract

Which two hormones are used in the posterior pituitary?

oxytocin and Antidiuretic hormone aka vasopressin

What part of the hypothalamus is oxytocin synthesized in?

paraventricular nucleus

What part of the hypothalamus is vasopressin synthesized in?

supraoptic nucleus

What is the role of oxytocin?

stimulates contraction of uterus and milk expulsion from mammary glands

What is the role of vasopressin?

increases water volume of blood and blood pressure

What kind of regulation is used in the posterior pituitary?

Neural regulation

What does oxytocin do?

Stimulates labor or menstruation by causing smooth muscle contraction in uterus. Also responsible for milk letdown in breastfeeding women by promoting contraction of smooth muscle like cells surrounding milk ducts

Why do we usually say its good for moms to breastfeed?

Stimulating nipples stimulates nerves that releases oxytocin, which allows expulsion of milk

What is antidiuretic hormone? What is another name for this hormone?

A water conservation hormone that prevents the output of large amounts of urine by promoting reabsorption of water. Aka vasopressin because it constricts blood vessels and raises BP

What is osmolality?

the concentration of solutes in a solution

How does osmolality relate to ADH?

If osmolality increases, more ADH is secreted so more water is retained, which reduces osmolality.

If osmolality decreases, less ADH is secreted so there is more urine, which increases osmolality

What does diabetes insipidus mean?

Diabetes = overflow Insipidus = no taste

What usually causes diabetes insipidus? What is happening to ADH?

Damage to the brain or brain trauma leads to decrease in secretion of ADH, leading to excessive urination due to imbalance of salt and water

Also can be due to kidney not recognizing ADH

What does "breaking the seal" mean? Why does this usually happen after you drink alcohol? With this in mind, what really is a hangover?

ADH is inhibited by alcohol.

Once you go to the restroom once, you have to keep going and going as it takes the endocrine system time for it to start making ADH and flushing out alcohol.

A hangover is really just the symptoms of dehydration (so technically you can get a hangover without even drinking).

What seven hormones are secreted by the ventral hypothalamus to act on the anterior pituitary?

Growth Hormone Releasing Hormone (GHRH)

Growth Hormone Inhibiting Hormone (somatostatin) (GHIH)

Thyrotropin RH = acts on thyroid to release its hormones

Corticotropin RH = acts on adrenal cortex via ACTH

Gonadotropin RH = acts on gonads via FSH and LH

Prolactin RH

Prolactin Inhibiting Hormone (dopamine)

What is another name for GHIH?

Growth Hormone Inhibiting Hormone

What six hormones are secreted by the anterior pituitary?

Thyrotropin aka thyroid stimulating hormone

Follicle stimulating hormone (sperm production and follicle maturation)

Luteinizing hormone (ovulation, gonadal hormone production)

Adrenocorticotropic hormone (ACTH)

Growth hormone aka somatotropin

Prolactin

What is another name for growth hormone?

somatotropin

Are the hormones from the anterior pituitary gland water or lipid soluble hormones?

water soluble

What is the role of FSH?

sperm production and follicle maturation

What is the role for LH?

ovulation, gonadal hormone production

What kind of regulation is used in the anterior pituitary?

hormonal

Are CRH and ACTH the same hormone?

NO

CRH goes to anterior pituitary, which releases ACTH (adrenocorticotropic hormone) and acts on adrenal cortex

What does growth hormone do?

Tells tissues to use fat instead of glucose for cellular respiration (so it can save it for the brain)

How does growth hormone affect fat reserves, amino acids and proteins, and glucose?

Increases uptake of amino acids and protein synthesis Increases breakdown of lipids

How is growth hormone hormone related to exercise?

Involved in recovery after working out

What does growth hormone do to sulfur?

Uptake of sulfur by cartilage matrix

What are direct effects of GH?

increased breakdown of lipids and the decreased use of glucose as an energy source

What are indirect effects of GH?

increase protein synthesis and growth of bone, muscles, etc.

What stimulates the secretion of GH?

Low blood glucose levels, stress, and rising amino acid levels

What inhibits the secretion of GH?

High blood glucose levels decrease secretion

What is gigantism caused by?

increased GH before bone ossification (childhood)

What is acromegaly caused by?

increased GH after bone ossification (adulthood)

What is dwarfism caused by?

decreased GH

How does GH fluctuate based on the time of day?

Rises during early stages of normal sleep cycle and peaks during deep sleep so you have most growth to occur during sleep

How does stress influence GH release?

Increases GH

In children, it can cause a decrease in GH release