Histology 412 Flashcards
Role of the posterior pituitary (3) and the histological structures in it that accomplish these roles (2)
Posterior pituitary stores and releases oxytocin and ADH. THey are synth in hypothal and tranported to post pit.
This is why the post pit consists of (1) unmyleinated axons of neurons that store these hormones. THe storage ends are called herring bodies.
stars: unmyelinated axons that are storing hormones.
A: Pituicytes - plump cells
B: Sinuisoidal capillaries
C: Herring bodies = the terminal bodies of axons where hormones are stored.
What are the cells of the anterior pituitary and what do they produce?
- The anterior pituitary synthesizes and secretes several hormones so there are many types of cells
- Chromophobes - little visible cytoplasm and do not stain well
-
Chromophils - the active cells; they have abundant cytoplasm filled with secretory granules
- Acidophils - smaller; secrete GH and prolactin
- Basophils - larger; secrete ACTH, FSH, LH, and TSH
Cells are chormophobes () and chromophils (). Chromophils include acidophils and basophils.
What is pictured? How do we know?
Adenoma of pituitary gland. SMall, relatively uniform cells, similar to those of a normal pituitary gland, but individual aciophils an dbasophls cannot be located.
The brown staining occurs in pieces of adenoma
Histological changes in acromegaly
Loss of normal glandular architecture. The cells are all of one type (secreting growth hormone)
What is this
A: ANterior Pituitary (aka adenohypophysis)
B: Intermediate lobe (of anterior pituitary)
C: Posterior lobe (aka pars nervosa; component of the posterior pituitary)
D: Posterior pituitary (aka neurohypophysis)
E: anterior lobe (aka pars distalis; component of the anterior pituitary)
F: pars tuberalis (component of anterior pituitary)
G: infundibular stalk
What is pictured?
Purpose of Pituicytes
Plump cells in the posterior pituitary that act like astrocytes do in the CNS - support the surrounding axons in the posteiror pituitary.
What is pictured?
A: chromophobes
B: acidophils
C: basophils
D: chromophils
Pituitary gland.
Normal pituitary gland tissue has a deliccate network of reticular fibres surrounding groups of pituitary cells.
What is pictured? How do we know?
Pituitary adenoma. Reticular fibres are not regularly arranged anymore.
what are these two pictures contrasting?
Brown staining on L is a pituitary adenoma. Right is the normal pituitary gland. The brown is a stain for growth hormone so this is what it would look like in acromegaly.
Crista ampullaris and macula are found in the ___(A)___;
Whereas, the organ of Corti is found in the ___(B)___.
(A) vestibular apparatus
(B) cochlea
The fluid inside the bony labyrinths is called
perilymph
The fluid inside the membranous labyrinth is called…
endolymph
the two major components of the inner ear are the…
cochlea and vestibular apparatus
Functions of the vestibular apparatus
- Detect motion
- Detect body position relative to gravity
What structure is pictured? What cell types are pictured here?
Cristae ampullaris
Explain how the hair cells function
Hair cells are located in the cristae ampullaris. Hair cells have stereocilia & kinocilium (sp?) that insert into the gelatinous coat above them, called the cupula. With angular acceleration, the gel moves and with it moves the cilia. This sends the impulse through hair cells to CN 8
What is pictured?
low magnification - cristae ampullaris.
High magnification - hair cell with stereocilia and kinocilia.
What is pictured?
macula
What is pictured?
This is a macula
A) Sensory hair cells and support cells
B) Otolithic membrane (gelatinous membrane that the cilia insert into)
C) Otoconia (darkly staining calcium carbonate crystals embedded in the otolithic membrane)
What is pictured?
Cross-section of the cochlea / Organ of corti (runs the entire length of the cochlea)
A: scala vestibuli (filled with perilymph)
B: Scala media (aka cochlear duct; filled with endolymph)
C: Scala tympani (filled with perilymph)
What is pictured?
Cochlear duct
A: Reissner’s (aka vestibular) membrane (roof of the cochlear duct)
B: Stria vascularis (lateral wall of the cochlear duct; produces endolymph)
C: Basilar membrane (floor of the duct; supportsthe organ of corti)
D: organ of corti
Describe the histology in this picture.
This is the organ of corti. It is also composed of hair cells and support cells. Hair cells also have apical stereocilia that insert into a gelatinous membrane above (=tectorial membrane).
A: cross-section of a row of inner hair cells
B: cross-section of 3 rows of outer hair cells
C: Tectorial membrane
What is pictured here? Can you identify all of the relevant parts?
organ of corti
What is pictured? What are the arrows pointing at?
Looking down on the outer 3 rows of hair cells in the organ of corti (tectorial membrane has been removed)
Yellow arrows: 3 hair cells
Fuschia: sterocilia of those hair cells
What is pictured?
THe auditory tube. This is an example of respiratory epithelium.
A: lining of the tube
B: seromucous glands
C: support tissue (either bone or cartilage, depending on the location of the section)
What is pictured?
External auditory meatus/canal
A: The lining of the canal is thin skin - stratified squamous keratinized epithelium
B: hair follicles
C: sebaceous glands
D: ceruminous glands
What is pictured?
A section of the external auditory canal, featuring the ceruminous gland structure.
A: Secretory cells (cuboidal; apocrine secretion of contents into the lumina)
B: myoepithelial cells
C: lumina
Name the labeled components in this eye section
A: cornea
B: lens
C: optic nerve
D: corneosclera
E: sclera (the component at the back of the eye)
F: Uvea (made up of three layers)
F1: Choroid (pigmented vascular layer under the sclera)
F2: ciliary body (has muscle epithelium and zonular fibres)
F3: Iris (associated with dilator and constrictor muscles)
G: Retina
Identify the 3 chambers of the eye
2 small chambers that contain the aqueous humour.
1) anterior chamber
2) posterior chamber
The large change is filled with vitreous body
3) ocular chamber
Where is the aqueous humor produced?
In the posterior chamber by ciliarly epithelium and small underlying capillaries on the ciliary processes. It flows anteriorly between the lens and iris and then passes through the pupillary aperture into the anterior chamber. Exits through the irido-corneal angle.
(process depicted in image)
What is being pointed out? What is its role?
Trabecular meshwork: Located in the irido-corneal angle. Resorbs aqueous humor and directs it into the endothelial-lined channel canal of schlemm, which then drains into the venous circulation.
What is pictured? Describe the structure of each indicated portion.
Iris.
A: Double cuboidal pigmented epithelium (continuous with epithelium covering the ciliary body)
B: Anterior surface (does not have an epithelial layer; composed of stroma filled with fbroblasts and belanocytes.
C: Constrictor pupillae (parasympathetic control; circular; reduces the size of the pupil when innervated)
D: Dilator pupillae (under sympathetic control; radially arranged; dilates the pupil)
What is pictured here? What is labeled?
This is a section of the lens.
A: lens capsule
B: lens epithelium - simple cuboidal epithelium; found only on the anteior side of the lens
C: Lens fibres - made up of elongated columnar epithelial cells that lack nuclei and are rich in crystalline protein
What is pictred? What’s their function?
Zonular fibres. Arise from lens capsule and connect to cilary body.
Anchor lens in fixed position.
A: zonular fibres
B: ciliar body
What is pictured? What is its histological structure?
Ciliary epithelium.
- Double layer of cuboidal epithelium.
- (A) Outer pigmented cell layer (the deeper layer) contains melanin and is in contact with thehighly vascularized stroma (B) of the ciliary body. The outer pigmented epithelium is continuous with the retinal pigmented epithelium in the posterior comparetment of the eye
- (C) inner non-pigmented epithelium (produces aqueous humor)
