Quiz 3 Flashcards
(20 cards)
What two parts is the nervous system split into?
- The Peripheral Nervous System(PNS), which interfaces with the environment
- The Central Nervous System(CNS), which is the information processor
How do the parts of the PNS interact with the nervous system and the environment?
The sensory systems are the primary afferents(neurons that transmit info towards the nervous system). The many different motor neurons are the primary effectors(neurons that transmit info away from the nervous system).
What are some types of motor neurons?
Main types are somatic motor neurons and autonomic neurons. some subtypes of autonomic neurons are Sympathetic neurons, Parasympathetic
neurons, and Enteric neurons
What two parts make up the CNS of the nervous system?
The brain and the spinal cord
What are the five sections of the nervous system?
Telencephalon and Diencephalon(both make up the forebrain), Mesencephalon(midbrain), Rhombencephalon/Myelencephalon & Metencephalon(hindbrain), and the spinal cord.
What are the stages of development of the CNS in embryos to infants?
- 1 month: the forebrain, midbrain, and hindbrain exist in a neural tube along back of embryo
- 5 weeks: the five sections of the brain are identifiable; first three sections are in the brain while two others are along the futture neck and back areas of the embryo
- child: cerebrum has formed from the Telencephalon, the diencephalon is surrounded by it, and the other three section exist below the cerebrum
What is the vasculature of the brain?
The Blood-Brain Barrier separates circulating blood and cerebrospinal fluid(CSF). This occurs because the endothelial cells surrounding them are restrictive to the point or tightly controlling diffusion in a fashion similar to semi-permeability. This barrier transports essentials such as O2, nutrients, etc. Water soluble objects through pores, lipid soluble directly through, and others through vesicular transport.
Where is the hypothalamus located? What is its structure?
Within the base of the Diencephalon section of the forebrain/directly above the pituitary gland.
It is a kidney bean shaped object nestled in the crease at the bottom of the brain
Where does the hypothalamus have direct and indirect control over the endocrine system?
The hypothalamus secretes hormones to other endocrine glands(pits!) which secret hormones; this is how the brain regulates hormones: through the hypothalamus!
Example of how hypothalamus has direct control over endocrine system
Posterior Gland: Direct control can be seen through the innervated capillary bed
pathway that the posterior gland use. The hormones secreted by the hypothalamic neurons(OTP and AVP) enter the pituitary capillaries straight into blood circulation.
Example of how hypothalamus has indirect control over endocrine system
Anterior Gland: Indirect control can be seen through the innervated hypophyseal portal system that the anterior gland uses. The hypothalamic neurons release the hormones to hypothalamic capillary, venules(veins), and lastly the pituitary capillary. These stimulate the ant.pituitary cells to release its hormones into circulation towards target cells.
What are magnocellular neurons?
They are relatively large cells found in the hypothalamic nuclei(specifically the PVN and SON); they project directly to the POSTERIOR pituitary.
What are parvocellular neurons?
They are relatively small cells which project to the ANTERIOR pituitary.
What is the function of parvocellular neurons?
Parvocellular neurons release two hormones(or peptides?) that regulate anterior pituitary cells’ release of anterior pituitary hormones. These hormones are releasing hormones and release-inhibiting hormones.
What is the function of magnocellular neurons?
Magnocellular neurons release two neuropeptides directly into circulation from the POSTERIOR pituitary gland. These hormones are Oxytocin(OT) and Vasopressin(AVP).
Choose 1-2 releasing hormones to memorize info for! All of these are hormones produced by parvocellular neurons of the hypothalamus!!!
- Thyrotropin-releasing
hormone is a releasing hormone that triggers thyrotropin and prolactin release by targeting thyroid gland(which affect metabolic rate). - Growth hormone-
releasing hormone is a releasing hormone that triggers growth hormone release by targeting body cells(which stimulates growth).
Choose 1-2 inhibiting hormones to memorize info for! All of these are hormones produced by parvocellular neurons of the hypothalamus!!!
Prolactin release-
inhibiting hormone
(dopamine) is a release-inhibiting hormone that inhibits prolactin release by targeting mammary glands(which affects their growth and secretion of milk).
Growth hormone
release-inhibiting
hormone (somatostatin) is a release-inhibiting hormone that inhibits growth hormone and thyrotropin release by targeting body cells(which affects growth).
What is a homeostatic feedback system?
A system that maintains stability through self-regulating feedback loops.
What is negative feedback in the endocrine system? Provide example(s).
Negative feedback is most important and performed by most endocrine glands as it is important for maintaining homeostasis.
Example shown through negative feedback loop between T4, hypothalamus, and anterior pituitary. The hypothalamus secretes Thyroid Releasing hormone(TRH) that stimulates the anterior pituitary to secrete Thyroid Secreting Hormone(TSH). TSH targets the thyroid glad which produces T4. Once enough T4 exist in the body, they begin to target the hypothalamus and the anterior pituitary and inhibits their production of TSH and TRH. Too much T4 leads to hypo- or hyper- thyroidism depending on T3/T4 presence.
What is positive feedback in the endocrine system? Provide example(s).
Positive feedback promotes the original action in an acceleratory fashion(makes the actions and its consequences happen more and more) and moves AWAY from homeostasis.
Example shown through childbirth and oxytocin release. When the baby’s head contacts the cervix(1), the cervix’s nerve impulses are sent to the brain(2). This leads to the brain stimulate the post. pituitary gland to release Oxytocin into the bloodstream towards the uterus(3 & 4). The OT stimulates uterine contractions and pushes baby towards cervix(5).
