Endocrine System Flashcards
What type of glands and tissues make up the endocrine system?
Ductless
What is the function of the endocrine system?
To secrete hormones directly into the bloodstream
These hormones then regulate the metabolic activities of different organs and tissues of the body in order to maintain homeostasis
What system does the endocrine system work in conjunction with? Which system exerts a slower more diffuse response?
Autonomic nervous system
Endocrine system
What structure coordinates the autonomic and endocrine system?
Hypothalamus of the brain
List the seven main endocrine organs
Pituitary Gland
Hypothalamus
Thyroid Gland
Parathyroid Gland
Adrenal Gland
Pancreas
Testes/Ovaries
What is the name given to the depression in the skull where the pituitary gland sits?
Hypophyseal fossa (sella)
In what cranial bone does the pituitary gland sit in?
Sphenoid bone
What air sinus has a close relation to the pituitary gland and hypothalamus? Where is it located in relation?
Sphenoid air sinus
Inferiorly
What other two structures lie in close relation to the pituitary gland and hypothalamus?
Optic chiasm
Thalamus
Where is the optic chiasm located in relation to the pituitary gland?
It lies superior to the pituitary gland
Where is the thalamus located in relation to the hypothalamus?
It lies inferior (anterior on cross section) to the hypothalamus
What clinical feature tends to arise when the pituitary gland enlarges? Why?
Bitemporal hemianopia
An enlargement of the pituitary gland impinges on the crossing fibres of the optic chiasm
What is bitemporal hemianopia?
A condition in which vision is missing in the outer half of both eyes
Which structure connects the pituitary gland to the hypothalamus?
The pituitary stalk
What three lobes make up the pituitary gland?
Anterior lobe
Intermediate lobe
Posterior lobe
What two other terms are used to refer to the anterior lobe of the pituitary gland?
Pars anterior
Adenohypophysis
What two other terms are used to refer to the posterior lobe of the pituitary gland?
Pars nervosa
Neurohypophysis
What other term is used to refer to the intermediate lobe of the pituitary gland?
Pars intermedia
What does the anterior lobe of the pituitary gland develop from?
Brachial arches
What does the posterior lobe of the pituitary gland develop from?
It is a continuation of the hypothalamus and pituitary stalk
What ventricle of the brain lies superior to the pituitary gland?
Third ventricle
What structure is connected to the posterior lobe of the pituitary gland?
Mamillary bodies
Which lobe of the pituitary gland is larger?
Anterior lobe
What pituitary gland lobe is glandular and secretes several hormones? How many hormones does it secrete?
Anterior lobe
Seven
What pituitary gland lobe is neuroendocrine and secretes several neurohormones?
Posterior lobe
What two neurohormones are secreted by the posterior lobe of the pituitary gland?
Oxytocin
Vasopressin (ADH)
What colour does the anterior pituitary lobe stain with a H&E stain?
Dark pink
What colour does the posterior pituitary lobe stain with a H&E stain?
Light pink
What three cells make up the pituitary gland?
Acidophilic
Basophilic
Chromophobic
What colour do acidophilic cells stain with a H&E stain?
Pink
What colour do basophilic cells stain with a H&E stain?
Light purple
What colour do chromophobic cells stain with a H&E stain?
Pale
What additional cell makes up the posterior pituitary lobe?
Non-myelinated axons
Where are the cell bodies of the posterior pituitary lobe axons located?
Hypothalamus
What are the two classifications of acidophil cells?
Somatrophs
Mammotrophs
What hormone do somatrophs produce? What is the target organ of this hormone?
GH
Chondrocytes, which are located within the epiphyseal growth plate
What hormone do mammotrophs produce? What is the target organ of this hormone?
Prolactin
Mammary gland
What are the three classifications of basophil cells?
Corticotrophs
Thyrotrophs
Gonadotrophs
What two hormones do corticotrophs produce? What is the target organ of each hormone?
ACTH - Adrenal gland
MSH - Melanocytes
What hormone do thyrotrophs produce? What is the target organ of this hormone?
TSH
Thyroid gland
What two hormones do gonadotrophs produce? What is the target organ of this hormone?
FSH - Sex organs
LH - Sex organs
What two arteries supply the hypothalamus and the pituitary gland? What are these arteries a branch of?
Superior hypophyseal artery
Inferior hypophyseal artery
Internal carotid artery
What does the superior hypophyseal artery supply?
The hypothalamus
Before this artery enters into the hypothalamus, it breaks up into the hypophysial portal system. These capillaries then supply the anterior pituitary lobe
What does the inferior hypophyseal artery supply?
The posterior pituitary lobe
How does the hypothalamus communicate with the anterior pituitary?
The hypothalamus releases ‘releasing hormones’ into the bloodstream. These hormones enter the anterior pituitary via the pituitary stalk to stimulate the production of other hormones
How does the hypothalamus communicate with the posterior pituitary?
The supraoptic and paraventricular nuclei in the hypothalamus secrete neurohormones which then travel down axons. They then terminate in the posterior pituitary lobe
Describe venous drainage of the pituitary gland and hypothalamus
They drain via hypophysial veins into the cavernous sinus
What structure is located anteriorly to the thyroid gland?
Larynx
What structure is located inferiorly to the thyroid gland?
Trachea
At what vertebral level is the thyroid gland located?
Between C5 and T1
What two structures is the thyroid gland located between?
Circoid cartilage
6th tracheal ring
What is the isthmus of the thyroid gland?
The bridge of tissue which connects the two lobes of the thyroid gland
Where does the isthmus lie opposite to?
The 2nd and 4th tracheal rings
What two strap muscles overlie the thyroid gland?
Sternothyroid muscle
Sternohyoid muscle
What two nerves supply the vocal cords of the larynx?
Recurrent laryngeal nerve
Superior laryngeal nerve
Where does the recurrent laryngeal nerve run between?
Trachea
Oesophagus
Where does the superior laryngeal nerve run between?
Superficial pharyngeal constrictor
Inferior pharyngeal constrictor
What is the superior laryngeal nerve a branch of?
The vagus nerve
What two arteries supply the thyroid gland?
Superior thyroid artery
Inferior thyroid artery
What is the superior thyroid artery a branch of?
Common carotid artery
What is the inferior thyroid artery a branch of?
Subclavian artery