Ch. 16 LEC - Endocrine System

what do the endocrine and nervous systems work together to do?

to coordinate the activity of body cells

the endocrine system works [FASTER/SLOWER] than the nervous system

slower

responses from the [ENDOCRINE/NERVOUS] system tend to last longer than that of the [ENDOCRINE/NERVOUS] system

endocrine, nervous

the endocrine system's response is delivered by [HORMONES/NEUROTRANSMITTERS] via [NEURONS/THE BLOODSTREAM]

hormones, the bloodstream

list the main 5 organs of the endocrine system

pituitary, thyroid, parathyroid, adrenal, and pineal glands (OTHERS: hypothalamus, thymus, pancreas, ovaries (female), testes (males))

true or false: all organs release hormones, but endocrine glands are unique because that is their main function

true

define “hormones”

long-distance chemical signals that travel in the blood or lymph

what are the two main classes of hormones?

amino acid-based (proteins) and steroids (cholesterol, fat)

how can hormones affect target cells? (5 possible answers)

alter plasma membrane permeability

stimulate synthesis of proteins

(de)activate enzymes

induce secretory activity

stimulate mitosis

complete these prompts for AMINO ACID-BASED HORMONES:

water solubility - [YES/NO]

receptor location - [MEMBRANE BOUND/INTRACELLULAR]

requires 2nd messenger - [YES & NAMES/NO]

carrier molecule - [YES/NO]

water solubility - YES

receptor location - MEMBRANE BOUND

requires 2nd messenger - YES, cAMP and PIP2

carrier molecule - NO

complete these prompts for STEROID HORMONES:

water solubility - [YES/NO]

receptor location - [MEMBRANE BOUND/INTRACELLULAR]

requires 2nd messenger - [YES & NAMES/NO]

carrier molecule - [YES/NO]

water solubility - NO

receptor location - INTRACELLULAR

requires 2nd messenger - NO

carrier molecule - YES

complete the steps of the cAMP signaling mechanism:

[AMINO ACID/STEROID] hormone (1st messenger) binds to [1]

[1] activates [2]

[2] activates [3]

[3] converts ATP to [4] (2nd messenger)

[4] activates protein kinases

amino acid

[1] receptor

[2] G protein

[3] adenylate cyclase

[4] cAMP

what types of hormones activate their target cells via intracellular receptors and direct gene activation?

steroid and thyroid hormones

define "target cell specificity"

target cells must have specific receptors to which the hormone binds

what 3 factors does target cell activation depend on?

blood levels of the hormone

number of receptors on/in the target cell

affinity of binding between receptor and hormone

define "up-regulation" in the context of how hormones influence the number of their receptors

target cells form more receptors in response to the hormone

define "down-regulation" in the context of how hormones influence the number of their receptors

target cells lose receptors in response to the hormone

how are hormones removed from the blood? (3 possible answers)

degradation via enzymes

kidneys: excretion via urine

liver: degradation via enzymes

what are the 3 ways multiple types of hormones interact with each other?

permissiveness, synergism, antagonism

define "permissiveness"

hormone A can't exert its effects without hormone B being present

define "synergism"

1+ types of hormones produce the same effects on a target cell

define "antagonism"

1+ hormones opposes the action of another hormone

hormones are synthesized and released in response to [3 TYPES OF STIMULI]

humoral stimuli

neural stimuli

hormonal stimuli

define "humoral stimuli"

change in blood levels of ions and nutrients stimulates secretion of hormones

define "neural stimuli"

nerve fibers stimulate hormone release (sympathetic nervous system)

define "hormonal stimuli"

hormones stimulate other endocrine organs to release their hormones

true/false: the nervous system modifies the stimulation of endocrine glands and their negative feedback mechanisms

true (e.g., glucose levels rise under severe stress)

what are the 2 major lobes of the pituitary gland?

anterior pituitary (adenohypophysis) and posterior pituitary (neurohypophysis)

what is the makeup of the posterior pituitary gland?

nerve fibers

what is the makeup of the anterior pituitary gland?

glandular tissue

list the hormones that the posterior pituitary gland releases

oxytocin

antidiuretic hormone (AH)

what is the “hypothalamic-hypophyseal tract”?

the neural pathway of axons that connects the hypothalamus to the posterior pituitary gland

what is the “hypophyseal portal system”?

the network of blood vessels that carries hormones and connects the hypothalamus to the anterior pituitary gland

list the hormones that the anterior pituitary gland releases

growth hormone (GH)

thyroid-stimulating hormone (TSH) or thyrotropin

adrenocorticotropic hormone (ACTH)

follicle-stimulating hormone (FSH)

luteinizing hormone (LH)

prolactin (PRL)

true/false: all anterior pituitary hormones are steroids

false - they are all proteins

define “tropic" hormone

a hormone whose target is another endocrine gland

list the 4 anterior pituitary hormones that are tropic

TSH, ACTH, FSH, LH

name the hormone that fits this description:

• secreted by the anterior pituitary gland

• stimulates most cells - targets mostly bone and skeletal muscle

• promotes protein synthesis

• encourages use of fats for fuel (elevates blood glucose by decreasing glucose uptake and encouraging glycogen (fat) breakdown)

  • anti-insulin effect of GH

• most effects are mediates indirectly by insulin-like growth factors (IGFs)

• stimulates liver, skeletal muscle, bone, cartilage to produce IGFs

growth hormone (GH)

hypersecretion of growth hormone (GH) in children results in _

gigantism

hypersecretion of growth hormone (GH) in adults results in _

acromegaly (enlarged feet, fingers, and/or tongue)

hyposecretion of growth hormone (GH) in children results in _

pituitary dwarfism

name the hormone that fits this description:

• secreted by the anterior pituitary gland

• stimulates the thyroid

• stimulated by thyrotropin-releasing hormone (TRH) released by the hypothalamus

• inhibited by high blood levels of thyroid hormones that act on the pituitary and hypothalamus

thyroid-stimulating hormone (TSH) (thyrotropin)

name the hormone that fits this description:

• secreted by the anterior pituitary gland

• stimulates the adrenal cortex to release corticosteroids

adrenocorticotropic hormone (ACTH) (corticotropin)

name the hormone that fits this description:

• is a gonadotropin, which is a hormone related to sexual development

• secreted by the anterior pituitary gland

• stimulates gamete (egg or sperm) production

• absent from the blood of prepubertal boys and girls

follicle-stimulating hormone (FSH)

name the hormone that fits this description:

• is a gonadotropin, which is a hormone related to sexual development

• secreted by the anterior pituitary gland

• promotes production of gonadal hormones (in ovaries and testes)

• absent from the blood of prepubertal boys and girls

luteinizing hormone (LH)

name the hormone that fits this description:

• secreted by the anterior pituitary gland

• stimulates milk production

prolactin (PRL)