Histology Etc.

Question 1

Function of collagen, elastin, reticular fibers:

Answer 1

Collagen: resist tension.
Elastin: allow for stretching.
Reticular fibers: form supportive meshwork.

Question 2

Scurvy

Answer 2

Vit C deficiency leading to UN-linked collagen.

Question 3

Ehlers-Danlos syndrome

Answer 3

Abnormal collagen synthesis leading to weak collagen.

Question 4

Marfan’s syndrome

Answer 4

Mutation in fibrillin-I, a component on elastin fibers. Targets CVS, skeletal oculars, etc.

Question 5

Main players in the ECM of CT (4)

Answer 5

Proteoglycans
Hyaluranon
Glycoproteins
EC proenzymes

Question 6

Embryonic CT

Answer 6

Rich in ECM and MSCs. Little collagen or reticular fibers.

Question 7

Function of LACT

Answer 7

Support and bind tissues, hold body fluids, defends against infection.
Found beneath epithelia, BVs, muscles, nerves.

Question 8

Function of Reticular CT

Answer 8

To hold free cells.

Found in liver, bone marrow, lymph nodes, etc.

Question 9

Dense irregular CT overview

Answer 9

Fibroblasts main cell type.
Resists tearing.
Found in dermis, organ capsules, perichondrium/periosteum, fascia.

Question 10

Dense regular CT overview

Answer 10

Fibroblasts main cell type.
Resists pulling.
Poorly vascularized.
Found in tendons, ligaments, aponeuroses, joint capsules.

Question 11

Where is elastic CT found?

Answer 11

BV walls, bronchioles, special ligaments.

Question 12

Fibroblasts produce:

Answer 12

Collagen, elastin, RFs, proteoglycans, glycoproteins.

Question 13

Hyaline cartilage overview

Answer 13

Has a perichondrium.
Type II collagen.
Articular cartilage, larynx, trachea, embryonic development.

Question 14

Elastic cartilage overview

Answer 14

Has a perichondrium.
Type II collagen.
External ear, epiglottis, auditory tube.
Hyaline + elastin.

Question 15

Fibrocartilage

Answer 15

No perichondrium.
Type I collagen.
IV disks, pubic symphysis, TMj.
Hyaline + dense regular CT.

Question 16

Articular cartilage is __________ and lacks a __________:

Answer 16

Hyaline, perichondrium.

Question 17

Territorial and interterritorial matrix

Answer 17

TM has less collagen and more GAGs than ITM.

Question 18

Perichondrium overview

Answer 18

Has blood supply.
Source of new cartilage.
Has 2 layers: fibrous, chondrogenic.

Question 19

Fibrous layer of perichondrium

Answer 19

Outer layer that produces type I collagen and elastin.

Question 20

Chondrogenic layer of perichondrium

Answer 20

Inner layer that differentiates into chondroblasts.

Secretes type II cartilage.

Question 21

Appositional growth overview

Answer 21

Cartilage formed on existing cartilage.

Undifferentiated cells –> chondroblasts –> secrete type II collagen and ground substance.

Question 22

Interstitial growth overview

Answer 22

Takes place within cartilage mass.
Chondrocytes divide in lacunae, forming new isogenous groups.
Increases in mass but is limited due to avascular nature.

Question 23

Zones of articular cartilage (4) superficial to deep:

Answer 23

Superficial zone
Intermediate zone
Deep zone
Calcified zone

Question 24

Layers of epidermis

Answer 24

Stratum corneum
Stratum lucidem
Stratum granulosum
Stratum spinosum
Stratum basale

Question 25

Epidermis is comprised of (4):

Answer 25

Keratinocytes Melanocytes Merkel cells Langerhans cells

Question 26

Strattum basale

Answer 26

Single layer of keratinocytes | Contains melanin.

Question 27

Stratum spinosum

Answer 27

Several layers thick. Has spiny processes. Can produce corns/callouses.

Question 28

Stratum granulosum

Answer 28

Thickest layer of non keratinized portion. Contains granules that assemble keratin into bundles. Irregularly shaped and variable in size.

Question 29

Stratum corneum

Answer 29

Anucleated cells. Filled with keratin. Forms water barrier.

Question 30

Keratinocytes

Answer 30

Most prominent cell. | Participate in epidermial water barrier.

Question 31

Basal cells

Answer 31

Synthesize keratin and group the into tonofibrils.

Question 32

Spinous cells

Answer 32

Keratin synthess continues and granules begin to bundle keratin and produce lamellar bodies.

Question 33

Granular cells

Answer 33

Discharge lamellar bodies. Continue to promote bundling of keratin via flaggrin. Cells now cornified.

Question 34

Melanin production

Answer 34

Premelanosomes begin producing melanin, then become melanosomes. Melanin transferred to keratinocytes via pigment donation.

Question 35

Langerhans cells

Answer 35

APCs that are monocyte precursors. | Identifyable in the stratum spinosum.

Question 36

Merkel cells

Answer 36

Function in cutaneous sensation. | Found in stratum basale and associated w/ nerve endings.

Question 37

Layers of dermis (2)

Answer 37

Papillary layer | Reticular layer

Question 38

Papillary layer has:

Answer 38

Collagen and elastic fibers. | Vaculature and nerve endings.

Question 39

Reticular layer is:

Answer 39

Irregular. Has type I collagen and elastic fibers. Forms Langerhans lines.

Question 40

Meissner's corpusle

Answer 40

Low frequency touch receptors. | Found in dermal papillae.

Question 41

Pacinian corpuscle

Answer 41

Detects pressure/vibration. | Found deep in dermis.

Question 42

Free nerve endings terminate in the:

Answer 42

Stratum granulosum. | Lack CT.

Question 43

Sebaceous glands

Answer 43

Produce sebum. Found alongside hair follicles.

Question 44

Eccrine sweat glands

Answer 44

Coiled and widespread. | Cholinergic activation.

Question 45

Apocrine sweat glands

Answer 45

Axilla, genitals, nipple, anus. Adrenergic activation. Uses merocrine secretion.

Question 46

Merocrine vs apocrine

Answer 46

Merocrine is in vescles. | Apocrine is a portion of cytoplsm being pinched off.