Anatomy (endo) Flashcards
What is the function of the hypothalamus and how does it achieve this?
Function= control of homeostasis
Integrates signals from internal organs and makes adjustments to internal environment (e.g. autonomic response, temp regulation, food/water intake) and endocrine control)
What are the boundaries of the hypothalamus?
its boundaries= (1) the anterior commissure and lamina terminalis anteriorly; (2) mammillary bodies and midbrain posteriorly, and (3) thalamus superiorly
What is the anterior commissure?
Extension of corpus callosum
What is the diamond shape seen below?
Floor of hypothalamus
What are mammilary bodies?
The mammillary bodies are brainstem nuclei on the posteroinferior aspect of the hypothalamus
What are mammilary bodies?
ADD FLASHCARD
The mammillary bodies are brainstem nuclei on the posteroinferior aspect of the hypothalamus
What is the thalamus made of?
Collection of nuclei (cell bodies within the nervous system)
What are two important nuclei in the hypothalamus connected to the endocrine system?
Paraventricular nucleus, has projections of axons into the posterior pituitary
Supraoptic nucleus also has projections
Both release oxytocin and vasopressin (ADH) into the blood stream at pituitary
What is another name for the pituitary?
The hypophysis cerebri
How are the pituitary and hypothalamus connected?
Via the infundibulum (pituitary stalk)
Where do the anterior and posterior parts of the pituitary arise from?
- Posterior = neurohypophysis = neuronal (is a swelling of the pituitary stalk distally)
- Anterior = adenohypophysis = epithelial (is upgrowth from root of primative oral cavity)
What are the red and blue circles?
Red= hypophyseal/pituitary fossa
Blue= Spenoid sinus
What is the shelf of dura that covers the roof of the pituitary fossa called?
Sellar diaphragm
What is the median eminence?
The median eminence is the structure at the base of the hypothalamus where hypothalamic-releasing and –inhibiting hormones converge onto the portal capillary system that vascularizes the anterior pituitary gland
How are cells divided up in the anterior pituitary?
cells are divided chromophills- about to secrete hormone/filled with hormone (B) and chromophobes- not fully of hormone (lightly stained)
What are the different releasing/inhibiting factors, the hormone they release and the effects of that hormone for the anterior pituitary?
How are anterior pituitary hormones released?
- Hormones released from the hypothalamus can both promote and inhibit hormone release from the pituitary
- Factors which control release are released from the terminals of hypothalamic nuclei into pituitary portal system, which has vascular sinusoids between secretory crells
What are the different cell types that release hormone in the anterior pituitary?
Do the anterior and posterior pituitary make their own hormone?
Anterior= YES
Posterior= NO
How does the posterior pituitary release hormones?
- Magnocellular neurons originate from the hypothalamus and terminate in the posterior pituitary
- Hormones are synthesized in magnocellular neuron
- Hormones pass down axons bound to glycoproteins through pituitary stalk where they are stored in the distended terminal end of the axon
- Release is controlled by nerve impulses = neurosecretion
What are the hormone pathways that occur in the posterior pituitary?
What are Herring bodies and Pituicytes?
Herring bodies- end of axons from hypothalamus-where hormone is released from, pituicytes- supporting cells
Where does the pituitary get its blood supply from?
Pituitary gets blood supply from superior and inferior hypophyseal artery (branches of the internal carotid artery)
What hormones does the thyroid produce?
Produces T3 and T4, regulates basal metabolic rate
Also releases calcitonin- regulates blood calcium levels
How is the thyroid stimulated?
By secretion of TSH from anterior pituitary
What are the 3 parts of the thyroid?
What arteries supply the thyroid with blood?
Superior thyroid artery (branch of external carotid)
Inferior thyroid artery (branch of subclavian)
How is blood drained from the thyroid?
Superior and middle thyroid veins (drains to internal jugular) and inferior thyroid vein ( drains in subclavian or brachiocephalic veins)
How many parathyroids do people have?
Variable in number, usually 4
What is the function of the parathyroid?
Secretes parathyroid hormone, regulates serum calcium and phosphate levels
What is the blood supply/ drainage to the parathyroid?
Supplied mainly by inferior thyroid artery
Drains to thyroid plexus of veins
What are the different cells present in the parathyroid?
- Chief/ principle cells= make hormone
- Oxyphil cells= unknown functiom
- Adipocytes= lots of fat present
What is the pancreas, and what is its function?
Accessory digestive gland
Produces exocrine and endocrine secretions
What are the endocrine secretions made from the pancreas?
Has pancreatic islets that contain:
- Alpha Cells- glucagon, Raise Blood Glucose
- Beta cells- insulin- Promotes uptake of glucose to lower blood glucose
- Delta cells- Somatostatin, Gastrointestinal function
Where is the pancreas located?
Posterior to stomach, between duodenum and spleen
What is the drainage system from the pancreas?
The venous portal system straight to the liver
What is the shelf of Dura covering the pituitary fossa known as?
Sellar Diaphragm
What structure passes through the sellar diaphragm and connects the pituitary gland to the base of the brain?
Infidibulum
Or pituitary stalk
What are the following labels?
What are the following labels?
Where are the cell bodies, axons and synapses of the magnocellular neurons located?
-Cell bodies: Supraoptic and Paraventricular nuclei of the hypothalamus
-Axons: Travel in the pituitary stalk
-Synapses: Posterior Pituitary
What structure is found immediately below the pituitary fossa?
The sphenoid sinus
What nerve do the superior and recurrent laryngeal nerves both originate from?
The vagus