(04) Endocrine System - Pituitary Gland Flashcards
- The endocrine system works with the nervous system to help maintain what?
- The electrical signals generated by the nervous system brings about what (via what)?
- The chemical signals (hormones) produced by the endocrine system are secreted into what or what? resulting in what?
- homeostasis
- rapid localized responses (via direct neural connections)
- interstitium or blood; local affect or wide spread response respectively
(Common Antomical features of endocrine organs)
- Ducts or no?
- cells are what in appearance? often arranged how?
- sparse connective tissue
- Vascular? often with what kinds of capillaries?
- none
- epitheloid; cords or clusters
- -
- yes - very much so; fenestrated (leaky) sinusoidal capillaries
- What modify the function of the “target” organs or cells?
2-5. What are the four structural groupoing of hormones?
- hormones
- peptides and proteins
- steroids (testosterone, estrogen)
- amino acid derivatives (thyroid hormones, epinephrine)
- fatty acid derivatives - Eicosanoids (prostaglandins)
- Hormones typically bind specific hormone receptors located where in target cells?
- Peptide type hormones… can they move through lipid membrane?
- lipid nature hormones…. can they move through membranes? bind where?
- The nuclear receptor activation results in what sequence?
- Give me three paries of endocrine cells and their hormones…
- on the surface or within (cytoplasm or nucleus) target cells
- no - bind to surface cell receptor (use second messengers)
- yes (plasma and nuclear); within target cell nucleus
- transformation of receptor –> binding to chromosomal DNA –> activation of RNA polymerase –> and so on and so forth
- beta cells of pancreas (insulin), interstitial cells of testis (tesosterone), follicular cells of ovary (estrogen)
(Pituitary Gland (Hypophysis))
- Pituitary gland sits in saddle-shaped depression of the what bone?
- Connected to the hypothalamus by what?also Functionally connected via what (that picks up what)?
- This gland has a complex and central role as a “relay station” - controlled by what thwo things?
- spenoid bone (sella turcica)
- a physical stalk of neural tissue (the infundibulum); vascular network (picks up hypothalamic derived neurosecretions)
- brain and by feedback from target organs
(Anatomical Divisions of Pituitary Gland)
1-2. What are the two divisions (plus give the embryologic origins)?
- neurohypophysis (a brain outgrowth)
- adenohypophysis (an oral cavity outgrowth)
(The development of the pitutary gland)
- The adenohypophysis develops as a pouch-like ectodermal outpocketing (hypophyseal cavity, aka Rathke’s pouch) from where?
- The neurohypophysis develops as a downward extension from where?
- The oral pouch surrounds the neural evagination as a what?
- What will be the pars intermedia of the adenohypophysis?
- The neural evagination that forms the neurohypophysis will remain physically connected to what?
- the rood the stomodeum (oral cavity)
- the floor of the hypothalamus (diencephalon)
- double-layer (a remnant of the pouch cavity may persist)
- the layer closest to the neurohypophysis
- this original nervous tissue of the diencephalon (the hypothalamus)
(Neurohypophysis)
- aka what?
- an extension of what?
- What are transported to the neurohypophysis (where they are stored and released as needed)?
- posterior lobe
- the nervous system
- HYPOTHALAMIC NEURON SECRETIONS
(Median Eminence of Neurohypophysis)
- Surrounds what?
- What pass through the median eminence?
- Axons terminals (Herring bodies) from the hypophysiotropic area of the hypothalamus secrete what?
- These secretions are then carried to what via what to affect what?
- infundibular recess (of the third ventricle)
- Axons (going from the paraventricular and supraoptic hypthalamic nulcei to neural lobe - the hypothalamo-hypophyseal tract)
- neurosecretory products (releasing/inhibitory factors) into this region
- the pars distalis via a venous portal system (to affect pars distalis cells)
(Infundibular stalk (or stem) of neurohypophysis)
- primarily a what?
- wat one specifically? from what areas of the hypothalamus?
- _a nerve tract _
- hypothalamo-hypophyseal tract from supraoptic and paraventricular areas of the hypothalamus
(Neural Lobe of the Neurohypophysis)
- aka what?
- Contains what of hypothalamo-hypophyseal tract?
- Some storage of what here?
- The neural lobe is functionally connected to what two nuclei?
- posterior lobe or pars nervosa
- axons terminals (Herring bodies)
- neurosecretory products
- hypothalamic supraoptic and paraventricular nuclei
(Neurosecretory products - hypothalamic origin)
- What type are found in Herring bodies in the region of the Median Eminence?
- Releasing and inhibitory factors (eg. growth hormone releasing hormone, growht hormone inhibiting hormone, thyrotropin releasing hormone, etc)
(Neurosecretory products - hypothalamic origin)
- What type are found in Herring bodies within the neural lobe?
* This hormone’s original name was vasopressin because it was observed that large (nonphysiologic) doses of the hormone resulted in contraction of the smooth muscle in vessel walls
- Main affect of this hormone is related to what? Released in response to what?
- What is the target (does what)?
- What does a deficiency lead to?
1. ADH (antidiuretic hormone, aka vasopressin)
- water homeostasis and osmolarity of body fluids; in response to decreased blood volume and/or increased osmolarity
- kidney distal tubules and collecting ducts (increases H2O permeability of ductal cells)
- nephrogenic diabetes insipidus
(Neurosecretory Products (hypothalamic origin):
- What type found in Herring bodies within the Neural Lobe?
- Promotes what?
- Targets what in female (+ does what)
- Induces what kind of behavior in females?
- In the male may function in what?
- oxycotin
- contraction of smooth muscle
- mammary gland myoepithelial cells (promotes milk letdown) and uterine smooth muscle (aids parturition and sperm transport)
- maternal behavior
- ejaculation (eg. by acting on smooth muscle of ductus deferens and/or epididymis) and sexual arousal
- Stromal cell of neurohypophysis is the what?
- helps do what?
- pituicyte (an astroglial-like cell with many processes)
- form structural support of structure