Flashcards in Anatomy 14 - Endocrine Deck (65)
what is a gland responsible for?
Manufacturing, storing and releasing at least 1 specific hormone
What happens do a hormone that is released by an endocrine gland?
It is secreted into the bloodstream to act at a distant target site(s) (cells displaying the correct receptor for the hormone are its target site)
What triggers a physiological response in the target cells?
Hormone binding to receptor
What type of processes do hormones control? (duration or speed)
Processes that require duration of action rather than speed of action (nervous system)
Why must the blood level of a hormone be controlled within the normal range?
To achieve homeostasis
What is homeostasis?
Maintenance of the bodies' physiological parameters relatively constant despite opposing external influences (conditions are necessary for normal cellular function)
What type of feedback mechanism almost always controls hormone levels?
What are the 2 types of endocrine gland tumours?
Functioning = too much hormone secretedNon-functioning = tumour destroys gland and too little hormone secreted
Apart from a tumour, how else may hormone negative feedback go wrong? (2)
Target cells sensitivity to hormone may changeInappropriate magnitude of cellular activity
2 main endocrine glands in the head?
HypothalamusPituitary gland (hypophysis)
5 main endocrine glands in the head?
4 parathyroid glandsThyroid gland
3 main endocrine glands in the abdomen?
2 adrenal (suprarenal) glands and the pancreas
2 main endocrine glands in the female pelvis?
2 main endocrine glands in the male pelvis?
What forms the central core of the cerebrum with connections to the right and left cerebral hemispheres and the midbrain?
What are the 2 parts of the diencephalon?
What are the 3 parts of the brainstem?
Where is the pituitary gland located in relation to the skull?
Midline structure in the pituitary fossa of the sphenoid bone
What anatomically and functionally connects the hypothalamus to the pituitary gland?
What is the pituitary anatomically and functionally divided into?
The anterior pituitary and posterior pituitary
Where do the axons of the hypothalamic neurones pass?
Down the infundibulum into the posterior pituitary
What 2 hormones does the hypothalamic neurones manufacture?
OxytocinVasopressin (ADH)(also releasing hormones or release-inhibitory hormones)
What are oxytocin and vasopressin transported to the posterior pituitary within?
The axoplasm (cytoplasm of the axons) by axoplasmic transport
In terms of the anterior pituitary, what does the hormones released from from the hypothalamic neurones either do?
Stimulate or prevent the anterior pituitary releasing hormones into the bloodstream
What hormones does the anterior pituitary release?(6)
GH (growth hormone)Prolactin (milk production)TSH (thyroid stimulating hormone)ACTH (adrenocoricotrophic hormone)LH (lutenising hormone - gonads)FSH (follicle stimulating hormone -ovaries)
How does the releasing hormones or release-inhibiting hormones pass into the anterior pituitary gland?
Hormones are released into the hypophyseal portal system These drain blood from the hypothalamus to anterior pituitary capillary beds (blood contains the release/ inhabiting hormones)
What drains venous blood from the anterior and posterior pituitary glands?
The hypophyseal veins which eventually drains the blood to the SVC
What is a portal system?
When a capillary bed lies between 2 sets of veins
Name 2 portal systems?
Hepatic portal systemHypophyseal portal system