Lecture 12 Review Flashcards
(32 cards)
What are the 4 types of chemical communications?
Neurotransmission, diffuse modulatory, autonomic, and endocrine
What is the periventricular part of the hypothalamus importance for?
Coordinating brain functions with the rest of the body
- circadian cycles (diffuse mod)
- ANS
- endocrine regulation
what does the SCN help coordinate? How does it do it?
Coordinates circadian rhythms by using mRNA-junctions
- cells coupled by gap junct
- it receives direct retinal innervation and projects to the brainstem to use the diffuse modulatory systems to coordinate the brain
- reticular formation controls transitions between sleep states
What are the NT used to ensue brain states?
Ach, 5HT, DA, Ne
What does the autonomic nervous system control?
the peripheral organ systems
- cardiovascular/lungs, gastrointestinal/digestive, reproductive
- it acts like a diffuse modulatory system throughout the body
Describe the sympathetic NS
fight or flight
- decreases digestion, increases respiratory function, increases HR and BP, makes glucose available
- preganglionic NT = Ach
- postganglionic NT = NE
Describe the parasympathetic NS
rest and repose
- reverses the effects of the sympathetic nervous system
- stores and conserves energy
- pre and postganglionic NT = Ach
When do the para and sympathetic nervous system work together?
During sex
- parasympathetic during arousal
- sympathetic during orgasm
What brain structure if critical for regulation of the ANS
the hypothalamus
- integrates forebrain/body states via hormones
What is the importance of the endocrine glands to the body?
they are involved in coordinating cell activity in every part of the body by releasing hormones
What’s the difference between neurotransmitters and hormones?
Hormones can be transported through the blood
What are the two types of hormones in the endocrine system?
Peptide and steroid hormones
What is there difference between a peptide hormone and a peptide neurotransmitter?
a peptide hormone has control of release and route to the target cell
Describe the characteristics of a peptide hormone receptor
all cell surface proteins - do NOT enter the target cell all receptors have enzymatic activity - kinases = phosphorylate - phosphates = dephosphorylates - can be directly enzyme coupled - can be G protein couples (initiates transcription)
Describe the characteristics of a steroid hormone
- all derived from cholesterol and are lipid soluble
- cannot be stored, released when synthesized
- levels of steroid regulated by control of synthetic enzyme activity that converts cholesterol to hormones (i.e. phosphorylation)
- the response to “release signal” is slow and prolonged
What are steroid receptors like?
- act as transcription factors
- can be in the cell
- can be localized onto membrane
• this allows for second messenger systems (much faster)
Describe the effects that steroid hormones can have
- can impact neurotransmission by modulating receptor responses
- can modulate channel-receptors and G protein coupled receptors
What is the relationship between the hypothalamus and the posterior pituitary? Together, what do they do?
- the hypothalamus have axons that project onto the posterior pituitary
- together they regulate many peripheral endocrine glands
What is considered the “master gland” of the endocrine system?
the paraventricular nucleus (PVN)
What hormones does the posterior pituitary release?
Vasopressin (ADH) and oxytocin
Describe oxytocin and how it affects the body
- its levels increase during sexual and intimate behaviors
- it promotes social bonding
- causes the uterus to contract during labor and stimulates milk in mammary glands
Describe vasopressin and how it affects the body
regulates blood volume and [salt]
- acts on kidneys
releases renin, which breaks down angiotensinogen I, breaks down into II
- directly affects kidneys and blood vessels to increase BP
- projected to hypothalamus to induce thirst
Describe the pathway between the hypothalamus and the anterior pituitary
- hypothalamus projects through the hypothalamo-pituitary vein
• carries hormones to AP - hypothalamus produces releasing hormones
- AP produces trophic hormones
What does the anterior pituitary do?
- responds to hormones from the hypothalamus and releases trophic hormones into general circulation
- it sends feedback to the hypothalamus
• hypothalamus regulates peripheral endocrine glands
