A&P test 1

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A&P test 1
2014-09-18 21:18:19
anatomy test1

go along with chaper 16 and 27
Show Answers:

  1. Distinguish between exocrine and endocrine glands.
    • exocrine: not hormones, secrete to the surface through ducts
    • endocrine: lack ducts, secrete hormones into the blood, well vascularized
  2. Compare and contrast the roles of the nervous system and endocrine system in
    maintaining homeostasis.
    • The Nervous System and the Endocrine System together act to direct the maintenance of homeostasis
    • – in other words, to control internal conditions.

    • Control by the Nervous System is rapid, localized (via nerve impulse transmission) and
    • relatively short-lived.

    • Control by the Endocrine System is slower, more global (hormones distributed through
    • circulatory system) and more prolonged.
  3. Define hormone
    long distance chemical signals, travel in blood or lymph.
  4. name and locate major endorcine organs
    • Pituitary
    • Thyroid
    • Parathyroids
    • Adrenals
    • Pineal
    • Thymus
  5. Why is the hypothalamus considered a neuroendocrine organ
    has both nervous and endocrine functions and tissues
  6. Hormones can be classifed by their chemistry, by solubility in water and by their
    mechanism of action. Name the classes for each category and explain the basis
    for classification
    • Chemistry: amino acid based derived from peptides proteins and amino acids steroids synthesized from cholesterol gonadal and adrenal cortical hormone 
    • Solubility: 1.Water-soluble hormones (all amino acid–based hormones except thyroid hormone)
    • •Act on plasma membrane receptors
    • •Act via G protein second messengers
    • •Cannot enter cell
    • 2.  Lipid-soluble hormones (steroid and thyroid hormones)
    • •Act on intracellular receptors that directly activate genes
    • •Can enter cell
    • Mechanism of action: •Though
    • hormones circulate systemically only cells with receptors for that hormone
    • affected target cells 
  7. how do hormones effect target cells
    • –Alter plasma membrane permeability and/or membrane potential by opening or closing
    • ion channels
    • –Stimulate synthesis of enzymes or other proteins
    • –Activate or deactivate enzymes
    • –Induce secretory activity
    • –Stimulate mitosis
  8. cAMP signalling mechanism
    • 1.Hormone (first messenger) binds to receptor
    • 2.Receptor activates G protein
    • 3.G protein activates adenylate
    • cyclase
    • 4.Adenylate cyclase converts ATP to cAMP
    • (second messenger)
    • 5.cAMP activates protein kinases that phosphorylate proteins
    • –Activated kinases phosphorylate various proteins, activating some and inactivating others
    • –cAMP is rapidly degraded by enzyme phosphodiesterase
    • –Intracellular enzymatic cascades have huge amplification effect
  9. PIP2-calcium signaling mechanism
    • –Involves G protein and membrane-bound effector – phospholipase C
    • –Phospholipase C splits PIP2 into two second messengers – diacylglycerol
    • (DAG) and inositol trisphosphate (IP3)
    • •DAG activates protein kinase; IP3 causes Ca2+ release
    • •Calcium ions act as second messenger
    • –Ca2+ alters enzyme activity and channels, or binds to regulatory protein calmodulin
    • –Calcium-bound calmodulin
    • activates enzymes that amplify cellular response
  10. What determines the ability of a target cell to respond to a hormone?
    blood levels to hormone, number of receptors on/in target cell, affinity of binding between receptor and hormone
  11. Describe the three ways that hormones influence each other’s activity at target
    • permissiveness:  multiple hormones must be present to produce effect
    • synergism: more than one hormone produces same effect on target cell-amplification 
    • antagonism: one or more hormones oppose action of another
  12. Name the anatomic regions of the pituitary gland. What is another name for the pituitary
    and for each region
    • pituitary (hypophysis) 
    • posterior lobe (neural)
    • anterior lobe (gladular)
    •  -adenohypophysis
  13. name hormones released by each part of the pituitary gland
    • posterior: store oxytocin and ADH(hormones made in the hypothalamus)  
    • anterior: GH, TSH, ACTH, FSH, LH, and PRL
  14. What is the hypophyseal portal system? What is its function?
    primary capillary plexus, hypophyseal portal veins, secondary capillary plexus carries releasing/inhibiting hormones to anterior pituitary to regulate hormone secretion *slide 62*
  15. What are the tropic hormones? Why are they called tropic?
    • regulate secretory action of other endocrine glands
  16. Name the 3 hormones produced by the thyroid gland. What is the function of each
    • Thyroid hormone: =>increase rate of cell metabolism = increased O2 use
    • & heat production
    • =>required for normal growth and development of nervous system

    • Extrafollicular cells secrete hormone calcitonin
    • a. Action = decrease [Ca++]blood by stimulating osteoblast activity in bone
    • b. Regulation by negative feedback:
    • =>high blood Calcium stimulates secretion
    • =>low blood Calcium inhibits secretion
  17. How is release of thyroid hormones regulated? How is release of calcitonin
    • thyroid hormone:
    • a. secretion stimulated by TSH
    • b. inhibited by negative feedback of ant pituitary, hypothalamus via rising levels of thyroid hormones
    • c. Consequences of misregulation:
    • hyposecretion in infants = cretinism
    • Grave’s disease = hyperthyroidism due to autoimmune stim thyroid
    • Calcitonin: 
    • Regulation by negative feedback:
    • =>high blood Calcium stimulates secretion
    • =>low blood Calcium inhibits secretion
  18. Describe
    the structure of the hormone producing structures of the thyroid
    • •Two lateral lobes connected by median mass called isthmus
    • •Composed of follicles that produce glycoprotein thyroglobulin
    • •Colloid (thyroglobulin + iodine) fills lumen of follicles and is precursor of thyroid
    • hormone
    • •Parafollicular cells produce the hormone calcitonin
  19. What is unique about the production of thyroid hormones?
    thyroid gland stores thyroid hormone extracellularly
  20. Name the hormone produced by the parathyroid glands and describe its action.
    Describe how it is regulated?