Histology: Integument, Soft CT, Hard CT Flashcards
What are the 4 basic tissue types?
Epithelial, connective, muscle, and nervous
What is the difference between gap junctions and tight junctions?
Gap junctions connect the cytoplasm of two adjacent cells, and tight junctions seal the space above and below the epithelium.
Name each layer
From bottom to top, stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum
What kind of tissue is this?
Lung epithelium
What kind of tissue is this?
Gut epithelium
What are the 5 functions of the epithelia?
physical protection, controls transport, move fluids across surfaces, produce speacial secretions, sensory functions
Name these types of exocrine glands
Top row: simple tubular, simple branches tubular, simple coiled tubular, simple acinar, simple branched acinar
Bottom row: compound tubular, compound acinar, compound tubulo-acinar
Name the mechanisms of secretion and explain them each
From left to right: merocine (release via excytocis), apocrine (cells release portions of themselves), holocrine (the entire cell distintergrates)
Name the functions of the layers of the epidermis: stratum basale, stratum spinsosum, stratum granulosum, stratum lucidum, stratum corneum
Stratum basale: where cell divison (mitosis) takes place
Stratum spinosum: responsible for the skin strength and flexibility, and they look spiny due to demosomes connecting the cells. When dehydration occurs, the cells look as though they have spikes
Stratum granulosum: helps form a waterproof barrier. the granules are due to the keratin structures in them
Stratum lucidum: it is responsible for the skins ability to stretch, it looks translucent (no nuclei), continues to provide a barrier to water
Stratum Corneum: they are sort of like pancakes that are waterproof, they prevent unwanted things from entering, and they prevent water loss
What is the difference between cornification and keratinization?
Cornification: braod term describing the formation of the horny layer of the epidermis
Keratinization: when the keratinocytes in the epidermis mature and here is polymerization of cytokeratin and undergo apoptosis to create the stratum corneum
What are melanocytes and where are they located?
They are the cells in the epidermis that produce melanin (skin pigment). They are located in the stratum basale.
What is a merkel cell and where are they located?
They are somatosensory cells that lie in the stratum basale and connect to the dermis (blood supply)
What are langerhans cells and where are they found?
They are immune cells that lie in the stratum spinosum.
What do arrector pili muscles for?
When they contract, the hairs stand on end (straight up).
Name the lettered structures.
A: Sebaceous gland
B: Hair bulb
C/D: Arrector pili
E: Sweat gland
What is this structure?
Sweat glans (Eccrine)
What are 6 functions of the integument?
- Protection against mechanical forces
- Waterproofing
- Keep unwanted things out
- Sensory
- Temperature control
- Raidiation barrier (Uv rays)
What types of forces does connective tissue need to deal with?
Tensile (rope pull) and compressive (squishing)
What molecule functions as the “rope” and what molecule functions as the “sponge”?
Collagen is our rope, hylauronic acid is our sponge
What are the big molecules that absorb water in connective tissues?
Proteoglycans
What kind of tissue is this and what is it for?
Loose areolar CT (messentary), to hold things together
What kind of tissue is this and what is it for?
Dense regular CT, for tensile forces (the rope to pull on).
What kind of tissue is this? What is it for?
Dense irregular CT, for combatting forces from several different directions
What kind of tissue is this? What is it for?
Hyaline cartilage (in the trachea), for resisting compression forces.
What kind of tissue is this?
Hyaline cartilage
What kind of tissue is this? What kind of forces can it combat?
Fibrocartilage, tensile and compression
What kind of tissue is this?
fibrocartilage
What kind of tissues are these?
elastic cartilage
What kind of tissue is this?
White adipose tissue
What kind of tissue is this?
Brown adipose
What kind of tissue is this?
Articular cartilage
What are the 3 main functions of the bone?
Mechanical functions (carrying loads)
Haematopoesis ( protecting the stem cells)
Calcium homeostasis
In our analogy for bones we used cocnrete and rebar. What forces are each of these strong against and what is their equivalent in bone structure?
Rebar is good against tension forces, and conrete is good against compression forces. For bones, collagen is the rebar and hydroxyapatite (calcium phosphate) is the concrete.
What is the difference between cortical bone and trabecular bone?
cortical bone is solid and trabecular bone is spongy
What is the difference between: osteocyte, osteoblast, osteoclast, and osteogenic cells?
osteocyte: mature cell no longer building, just hanging out
osteoblast: growing, adding, building on to the bone matrix
osteoclast: eats into bones, resorbs
osteogenic cells: stem cells in the bone
Name structures A and B
A: osteoclast
B: osteoblast
Name the structures
A: fibrocartilage
B: osteoblasts
C: bone
D: osteocytes
E: chondrocytes
F: osteoclasts
G: calcified cartilage
What kind of bone is built when you need to repair an injurt really fast?
Woven bone
What kind of bone is the more permanent kind?
Lamellar bone (Haversian)
What is intramembranous bone formation?
The bone will start growing in random places and the blobs eventually come together and fuse. This is a faster way to make bone.
What is endochondral bone formation?
This is when the bone structure will start out as hyaline cartilage, it then calcifies, and then osteoclasts eat away at it and replace it with actual lamellar bone
What are the steps in endochondral ossification?
proliferation, hypertrophy, calcification, erosion, ossification
Why do haversian systems appear circular in a cross sectional cut?
the blood vessels are located in the middle, so the bone is formed around the vessel, and the edges eventually close making a circular structure around the vessel
what is a bone multicellular unit made of?
FIrst you have the cutting zone where you’ll find the osteoclasts, then the reversal zone where osteoblasts will be making new cells, then the closing zone where there are no cells and the layers “close” together.
What are the components of red bone marrow?
hematopoeitic stem cells ( develop into all different kinds of blood cells)
mesenchymal stem cells (can develop into several different things)
endothelial stem cells
stromal/dendritic cells (hols stuff together)
megakaryocytes (make platelets)
What are the compnents of yellow bone marrow?
adipocytes (fat)
stromal cells (just hang out)
Identify what this structure is and what structures give it away
it is bone marrow because we can see the adipocytes (big white ones), but they are sort of spread out and not finely packed like it would be in just adipose tissue. We can see some megakaryocytes which are the bigger cells sometimes with multiple neuclii. You can also see if multiple smaller cells which would include hematopoietic cells.
AS the chondrocytes move from the fibrocartilage closer to the calcified bone they become more rounded rather than flat. Why?
Because rounder cells are resistant to compressive forces, so when a tendon insertion inserts to a bone, you will go from a collagen/rope like fibrocartilage to a more hyaline looking cartilage before mineralization occurs.
What is an osteon?
One unit/function of the multicellular unit. Also known as a “haversian system”.
What kind of tissue is this? How do you know? What is the arrow pointing to?
This is bone. You can tell because of the organized structure of the osteons and osteocytes. There are osteoblasts visible as well as some osteoclasts. The arrow is pointing to a little gap which is a reminant of once calcified cartilage that has been chewed away and just not rebuilt in that specific spot (during bone formation).
Identify each stage in endochondral ossification in this picture.
Proliferation, hypertrophy, calcification, erosion, ossification.
