Anatomy and Cell Biology 3309 Lecture Notes - Lecture 34: Pars Intermedia, Periventricular Nucleus, Posterior Pituitary
2 May 2018
School
Department
Professor
Histology Lecture 14 – Semester 2
Pituitary Gland
- Pituitary gland integrates the nervous system (what we receive as input form our environment) with
reactions that are based on hormonal secretions
- Vast majority of the glands are regulated by the master control gland, the pituitary gland
- Connection between cells that secrete hormones and the nervous system is very important
o Blood supply is important factor of the organization of the pituitary gland
Learning Objective
- Name the two main divisions of the pituitary gland and list their parts
- Describe the development of the pituitary, including the derivation of its divisions.
- Describe the blood supply of the pituitary gland
- Name the five main cell types in the pars distalis and list the hormones they secrete
- Explain the functions of anterior pituitary hormones
- Name the components of the neurohypophysis
- Name the hormones released in the pars nervosa and explain their function
- Describe the significance of pituicytes and Hering bodies
- Explain the relationship between hypothalamic nuclei and pituitary hormone release
- Pituitary gland is significant that there is protection of bone surrounding it
o Infication of the importance of the gland, due to the bone protection
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Embryonic Development
- Early on, we have two regions of our anatomy that come together to form the pituitary gland
- Starts off with the floor of the diencephalon (neural epithelium)
o Starts an outgrowth towards the roof of the mouth (epithelial cells)
o Nervous tissue and epithelial cells come together – they interact structurally and
functionally with one another
- Nervous tissue forms stock like structure, and the epithelium forms a loop
o Loop closes on itself and forms Rathke’s Pouch
o In the adult, there is evidence of the Rathkes Pouch
- As the gland develops, you can distinguish several regions that gives the gland its name
- Have two lobes developing
o One posterior lobe = Pars Nervosa (nervous part of the pituitary gland)
▪ Nervous tissue
o One anterior lobe = Pars Distalis
▪ Located distal, away from the pars nevosa
- Tissue of the anterior lobe that lies adjacent to the pars nervosa = Pars intermedia
o Part of Rathke’s Pouch
o Pars intermedia has NO special function that is different from the Pars Distalis
o Structure that you will be able to recognize in histological section
- Pars Tuberalis
o Anterior lobe, epithelial part of the pituitary gland wraps around the stop like structure that
comes from the diencephalon (nervous tissue)
o Forms tube like wrapping around
- Diagram of the mature/developed pituitary gland
- Made in part of nervous tissue, it lies directly under part of the brain that further develops =
hypothalamus
o Hypothalamus and the pituitary gland communicate because part of the pituitary gland is
nervous tissue
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- In the hypothalamus, there are three regions (nuclei)
o Nuclei = regions where there are cell bodies of neurons
o Concentrations of cell bodies develop the capacity to produce hormones. Rather than
signaling electrically, they produce signaling molecules (like neurotransmitters) that are not
designed to stimulate other nerves, but be released into the blood stream
o There re 3 nuclei
▪ Two of them are periventricular nuclei (next to ventricle, adjacent to hypothalamus)
and supraoptic nuclei (sitting over a region where the optic nerve cross, the optic
chiasma) these two regions of nuclei send axons right into the pars nervosa
o Pars nervosa receives axons from the periventricular and supraoptic nucleus
o Posterior lobe of the pituitary is also called the neurohypophysis
▪ Where most of the axons and glial cells coming from the hypothalamus
o Axons pass through this stoc that is infundibulum
o Infundibulum is divided into two regions
▪ Median Eminence = Adjacent to the brain
• FUNCTIONALLY, IT IS THE LOCATION WHERE AXONS OR NERVE CELL
PROCESSES END
• NERVE CELL PROCESSES COME FROM THE THIRD NUCLEUS,
HYPOTHALAMOHYPOPHYSIOTROPIC NUCLEI
• Tells you, that these nuclei are located in the hypothalamus, and feed the
anterior lobe of the hypophysis
▪ Infundibular process
- Anterior lobe of the hypophysis (endothelial tissue) = adenohypophysis
o Adeno = epithelial
- Pars Tuberalis = extension of the adenohyphysis that wraps around the infundibulum
- ANOTHER NAME FOR PITUITARY GLAND = HYPOPHYSIS
** KNOW THIS DIAGRAM AND TERMS AND UNDERSTAND HOW THE NERVOUS TISSUE RELATES TO
THE EPITHELIAL TISSUE
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Document Summary
Pituitary gland integrates the nervous system (what we receive as input form our environment) with reactions that are based on hormonal secretions. Vast majority of the glands are regulated by the master control gland, the pituitary gland. Connection between cells that secrete hormones and the nervous system is very important: blood supply is important factor of the organization of the pituitary gland. Name the two main divisions of the pituitary gland and list their parts. Describe the development of the pituitary, including the derivation of its divisions. Describe the blood supply of the pituitary gland. Name the five main cell types in the pars distalis and list the hormones they secrete. Name the hormones released in the pars nervosa and explain their function. Describe the significance of pituicytes and hering bodies. Explain the relationship between hypothalamic nuclei and pituitary hormone release. Pituitary gland is significant that there is protection of bone surrounding it.
