Lecture 2: Microanatomy & Histology Flashcards
What are the 4 basic tissue types?
1.) Epithelia
2.) Connective Tissue
3.) Muscle Tissue
4.) Nervous Tissue
What are the 3 germ layers from embryonic development from which all tissues are derived?
1.) Ectoderm
2.) Mesoderm
3.) Endoderm
3 important parts of the ECTODERM
1.) Neuroectoderm (neural tube)
2.) Neuroectoderm (neural crest)
3.) Surface Ectoderm
Structures derived from the NEURAL TUBE (Can Robots Pee Periodically?)
(Can Robots Pee Periodically?)
C - central nervous system
R - retina
P - pineal body
P - posterior pituitary gland
Structures derived from the NEURAL CREST
- Cranial & sensory ganglia / nerves
*adrenal medulla
*melanocytes
*pharyngeal arch cartilages
*head mesenchyme & connective tissue
*Schwann cells - Odontoblasts
What are Schwann cells?
Major glial cell of the peripheral nervous system.
What are Odontoblasts?
Cells that produce dentin & protect teeth.
Structures derived from the SURFACE ECTODERM
- Epidermis
*Hair & nails
*Cutaneous & mammary glands
*Anterior pituitary gland
*enamel
*internal ear
*corneal epithelium & lens
4 important parts of the MESODERM
1.) Head mesoderm
2.) Paraxial mesoderm
3.) Intermediate mesoderm
4.) Lateral mesoderm
Structures derived from the HEAD MESODERM (CCD)
*cranium
* connective tissue of head
*dentin
What is the Dentin?
A layer of material that lies immediately underneath the enamel of the tooth
Structures derived from the PARAXIAL MESODERM
*Skeletal muscle (not cranium)
*muscles of head
*dermis of skin
*connective tissue
Structures derived from the INTERMEDIATE MESODERM
*urogenital system (gonads, ducts, glands)
Structures derived from the LATERAL MESODERM (6)
- connective tissue and muscle of viscera
*serous membranes of pleura, pericardium, & peritoneum - blood & lymph cells
*cardiovascular & lymphatic systems - spleen
*adrenal cortex
Structures derived from the ENDODERM (ENDO = EPI)
*Epithelial parts & linings
Lining - resp tract, gi tract, bladder & urachus
Epithelial Parts - thyroid, tympanic cavity, auditory tube, tonsils, parathyroids, liver, pancreas
What is a dermoid cyst (teratoma)?
a type of cyst found almost exclusively in the ovaries, can have structures from all 3 germ layers.
Describe the general characteristics of Epithelial tissue.
*cover body’s surface, line cavities, form glands
*avascular (get from connective tissue)
*joined by specialized junctions
* surface specializations
* separated from underlying tissue by basal lamina
What is the basil lamina?
By what two characteristics do we classify epithelia?
1.) Number of Layers
2.) Cell Shape
Number of layer categories for epithelia
1.) Simple = 1 layer
2.) Stratified = 2+ layers
3.) Pseudostratified = appears 2+ but is only 1
Cell shape categories for epithelia
1.) Squamous = flat
2.) Cuboidal = square
3.) Columnar = tall
What is transitional epithelia?
a special kind of tissue found exclusively in the urinary system.
Describe the general characteristics of Connective tissue.
- derived from mesoderm
*separated from each other by extracellular matrix
What are the two classifications of connective tissue?
1.) Dense - more fibres (collagen) than cells
2.) Loose - more cellular (usually under epithelia)
What is adipose?
Fatty tissue, common in abdominal areas and around coronary vessels.
What are some examples of specialized connective tissues?
Bone, cartilage, and blood
Regular pattern of connective tissue
typical of ligaments and tendons
What is the function of fibroblasts?
Form connective tissue by excreting collagen
What color does collagen stain under H&E stain?
Pink
What color do proteoglycans stain under H&E stain?
Blue
What are proteoglycans?
Describe the general characteristics of Muscle tissue.
- derived from mesoderm
- help with temperature regulation & movement
What are the two basic types of muscle tissue?
1.) Striated (skeletal & cardiac)
2.) Smooth
Describe skeletal muscle tissue
large cells, long cylindrical, multinucleate, peripheral nuclei, usually voluntary
Describe cardiac muscle tissue
branched cells, central nuclei, connected by intercalated discs with gap junctions for comms. Non-voluntary
Describe smooth muscle tissue
fusiform, no striations, common in layers, small cells, look like round targets in cross sections.
3 important parts of the nervous system (tissues)
1.) Peripheral Nervous System (PNS)
2.) Autonomic Nervous System (ANS)
3.) Central Nervous System (CNS)
What is the Node of Ranvier?
Describe the PNS
- derived from neural crest
*sensory neurons in ganglia
*motor neurons in spinal cord anterior horn or brain stem motor nuclei
*Schwann cells myelinate axons
Describe the ANS
*2 parts - sympathetic & parasympathetic
sympathetic -
parasympathetic -
Where are preganglionic sympathetic neurons found?
lateral horn of thoracic spinal cord
Where are preganglionic parasympathetic neurons found?
brainstem nuclei or sacral spinal cord
Where are postganglionic neurons found?
in the ganglia
Describe the CNS
- brain & spinal cord
- oligodendroglia cells myelinate axons
