hormone basics Flashcards
(58 cards)
describe the role of the nervous system
to translate or transduce external stimuli into neural signals that bring change to the connected system
list some key aspects of the nervous system
Afferent neurons, Spinal cord, Effrent neurons, Target tissues, Hypothalamus,
what is an efferent neuron
Neurons which are nerves that travel away from the spinal cord towards target tissue
What is an afferent neuron
Sensory neurons taking signals towards the spinal cord
what are the two reflexes that control the neuroendocrine system
Simple neural reflex
neuroendocrine reflex
describe the simple neural reflex arch and name two examples
senory pick up by neurons -> signal sent to spinal cord via afferent neurons -> efferent neurons send back signal to target tissue with adjustment to response to stimuli.
ejaculation (touch stimuli and muscle contractions response)
scrotum tempreture (tempretur stimuli, contraction elevation of testes in response)
what is a neurotransmitter
substance/ small molecule released from the terminals of nerves that cause other nerves to fire or cause contraction of smooth muscle.
describe the neuroendocrine reflex and give an example
sensory neruon (affrenet) send signal to spine -> signal travels to hypothalamus (efferent) -> hypothalamus releases moleculs into blood (neurohormones)
what is an inhibitory neuron
Inhibitory neurons stop / prevent actions caused by other excitatory neurons.
what is an excitatory neuron
Neurons which increase the probability of postsynaptic action potential (firing nerves)
what does the probabilty of postsynaptic neruon firing relay on?
ratio of presynaptic inhibition to presynaptic excitation.
what is the hypothalamus
The hypothalamus is a complex portion of the brain. It is made from clusters of nerve cell bodies called hypothalamic nuclei, each one having a specific name and function.
where is the surge center and what does it produce
in the hypothalamus, it produces Gonadotropin Releasing Hormone (GnRH)
what allows for neuron communication in the hypothalamus and what is it made of?
via the anterior lobe of the pituitary using a specialized system called the hypothalamo - hypophyseal portal system. This system is a capillary network connected to terminal nerve endings.
how does the hypothalamo - hypophyseal portal system function?
Terminal boutons release neuropeptides which enter the blood from the superior hypophyseal artery.
The hypothalamic-hypophyseal portal is important as it allows small quantities of releasing hormones to act directly on the anterior lobe of the pituitary before the GnRH becomes diluted by the systemic circulation
does the prosterior pituitary lobe have a portal system?
No, instead the neurohormones are deposited straight into the capillaries.
what is a hormone
substance produced by a gland that acts on a REMOTE tissue, these can include changes to metabolism, synthetic activity, and secretory activity.
what is a luteolytic hormone
Hormones which cause destruction to the corpus luteum (PGF2a) prostaglandin F2a
list endocrine glands important to the reproductinve system (obviously)
Anterior pituitary gland
Posterior pituitary gland
Uterine
Placenta
Ovaries
Testes
Thyroid gland
Adrenal cortex
Endocrine gland
what hormone does the hypothalamus mainly produce
Gonadotropin releasing hormone (GnRH)
what does the Anterior pituitary gland release?
Follicle Stimulating hormone (FSH), Luteinizing hormone (LH), prolactin, somatropin (growth hormone)
what does the posterior pituitary gland release
oxytocin
what hormone does the uterine release
prostaglandin F2a (PGF2a)
what hormone does th placenta release
progesterone, estrogen (estradiol) , equine chorionic gonadotropin (eCG), human chorionic gonadotropin (hCG), placental lactogen, Acitvin