bio 252 Flashcards
4 types of intercellular communication
- gap junctions through cytoplasm
- neurotransmitters through synaptic cleft
- paracrines through interstitial fluid
- hormomes through the blood
what are hormones traveling through blood important?
They illicit a systemic response, cell to cell communication, travel great distance.
principles of hormone communication
- hormones are released by endocrine glands (endocrine cells, neuroendocrine glands)
- Picked up by blood
- hormones travel throughout the body
- hormones “diffuse” out of the capillaries
- hormones stimulate “target cells”
what is different about target cell capillary in hormone communication
target cell capillaries are fenestrated, basically look like windows where the hormone comes in. more surface area.
endocrine system and communication
- communication by hormones
- releases hormones to blood
- potentially widespread effect
- slow response
- long lasting
what is a humeral stimulus?
where the hormone released in response to ion levels in the body, ex. parathyroid glands and calcium.
neural stimulus
hormone release caused by neural input.
ex would be CNS releasing preganglionic sympathetic fibers, to medulla of adrenal gland to release epi.
hormonal stimulus
a hormone release caused by another hormone (a tropic hormone). Ex. Anterior pituitary gland to release other hormones.
function of hypothalamus
located in the third ventricle of the brain, controls water balance, thermoregulation, sex drive, childbirth and various autonomic functions. many functions executed by pituitary gland.
how can hypothalamus exert control over pituitary gland.
nervous system signals and endocrine signals
why is the pituitary gland divided into two parts?
anterior parts communicates via hormones, posterior part communicates through nervous system.
the connection between hypothalamus and anterior pituitary gland?
vascular connection, still uses hormones but communication is through blood making it vascular. the system is called Hypothalamo-hypophyseal Portal System
ADH antidiuretic hormone
stimulus - high blood osmolarity
messenger- ADH
response- increase water retention
increase thirst
oxytocin
stimulus- neural stimulus (specifically during childbirth)
messenger- Oxytocin
response- smooth muscle contraction (uterus, reproductive ducts, and mammary glands) promotes emotional bonding.
anterior pituitary hormones released when stimulated by hypothalamic hormones / trophic because their role is release other hormones.
Gonadotropin- releasing hormone Thyrotropin- releasing hormone Corticotropin- releasing hormone Prolactin- inhibiting hormone Growth hormone- releasing hormone growth hormone- inhibiting hormone (somatostatin)
