Histology 2

Front 1

Integument consists of ______

Back 1

Skin and derivatives (nails, hooves, feathers, etc.)

Front 2

The 3 layers of the skin are:

Back 2

1- Epidermis (the skin we see)
2- Dermis
3- Hypodermis

Front 3

The 3 glands of the integument are:

Back 3

1- Sebaceous
2- Sweat
3- Mammary

Front 4

The are 4 main layers of the epidermal layer:
And one that occurs only in thick epidermis (i.e. footpad, nose, teat):

Back 4

1- Stratum corneum (many layers
2- Stratum granulosum (1-4 layers)
3- Stratum spinosum (2-5 cells thick)
4- Stratum basale (1 layer)

1- Stratum lucidum (when it does occur, it is between corneum and granulosum)

Front 5

The _______ is flat, cornified - dead.

Back 5

Stratum corneum

Front 6

The _________ is a translucent squamous layer (organelles absent). It is limited to only thick epidermis such as the footpad, nose, teat, etc.

Back 6

Stratum lucidum

Front 7

The ___________ is flat polygonal cells with basophilic granules.

Back 7

Stratum granulosum

Front 8

The ____________ is cuboidal to squamous.

Back 8

Startum spinosum

Front 9

The __________ is attached to the basement membrane by hemidesmosomes.

Back 9

Stratum basale

Front 10

Stem cell are located in which epidermal layer?

Back 10

Stratum basale

Front 11

In the stratum basale, ________ is abundant

Back 11

mitosis

Front 12

The stratum basale has spots of ________ pigment.

Back 12

melanin

Front 13

________ is tonofilaments of keratin. It is held together by desmosomes and capable of mitosis.

Back 13

Stratum spinosum

Front 14

__________ has keratohylain granules which make keratin. Makes hard keratin which makes up hair, feather, hooves, etc. by disulfide bonds. Soft keratin makes up the outer layer, the corneum.

Back 14

Stratum granulosum

Front 15

________ is tough, protective skin that is keratinized with soft keratin.

Back 15

Stratum corneum

Front 16

What are the four types of epidermal cells?

Back 16

1- Keratinocytes

2- Melanocytes

3- Langerhans cells (dendritic cells)

4- Merkel's cells

Front 17

_________ divide and differentiate into outer protective cell layers. They form all the layers, basal, spinosum, granulosu, and corneum.

Back 17

Keratinocytes

Front 18

____________ are derived from the neural crest during development and are located between keratinocytes near the basement membrane. Special stains are needed to see them.

Back 18

Melanocytes

Front 19

_________ secrete melanin granules - taken up by keratinocytes. The melanin accumulates over the nucleus to protect it from ________.

Back 19

Melanocytes;

UV light

Front 20

Melanocytes produce _________ in red skin/hair instead of melanin.

Back 20

pheomelanin

Front 21

Black skin/hair has _____ of melanin, while fair skin/hair has _______ melanin.

Back 21

Lots;

Almost no

Front 22

UV rays _______ production of melanin.

Back 22

Increase. The more time spent in UV rays, the more melanin released, the darker a tan will become.

Front 23

_________ are derived from monocytes, have cytoplasmic extensions, contain large granules called Birbeck granules.

Back 23

Langerhans cells

Front 24

_______ have antibodies at their surface to trap antigens and present them to lymphocytes. They are non-phagocytic but migratory. They are most prominent in stratum spinosum (also occur in the papillary dermis).

Back 24

Langerhans cells. They are hard to see without special stains.

Front 25

__________ are slow adapting mechanoreceptors for touch and are located within the basal layer. They are neuroendocrine cells with dense core granules. Myelinated axons terminate on them.

Back 25

Merkel's cells. They require special stains and can form tumors, Merkel cell carcinoma.

Front 26

________ are derived from epidermis and are located in the reticular layer of the dermis (sometimes even deeply into hypodermis), but are connected stratum basale.

Back 26

Hair follicles.

Front 27

The four major components of a hair follicle are:

Back 27

1- Internal root sheath

2- External root sheath

3- Dermal papilla

4- Hair matrix

Front 28

The _____ of a hair follicle is the glassy membrane.

Back 28

Thick basal lamina

Front 29

The ________ of the hair follicle goes up to sebaceous glands.

Back 29

Internal root sheath

Front 30

The _________ of the hair follicle is made of keratinized shingles.

Back 30

cuticle

Front 31

The _________ of the hair follicle is made of keratinized cells with melanin granules

Back 31

cortex

Front 32

The ______ of hair follicles are keratinized central cuboidal cells. Present in large hairs only.

Back 32

medulla

Front 33

The _______ of a hair follicle is the capillary network around follicles and glands.

Back 33

cutaneous plexus

Front 34

There are 3 types of hair:

Back 34

1- Primary (Guard)

2- Secondary (wool)

3- Sensory (sinus or tactile)

Front 35

_________ hair has a large diameter, deep root, and has sebaceous and sweat gland, and arrector pili.

Back 35

Primary. They occur in horses, cows, and some dogs. Come single or in compound follicle.

Front 36

_______ hair has no medulla, no sweat gland, nor pili muscle. Has a shallow root.

Back 36

Secondary

Front 37

_______ hair are whiskers (vibrissae), in blood sinuses and nerves, and some skeletal muscle.

Back 37

Sensory

Front 38

The formation of the hair follicle is very similar to the formation of any other skin structure, such as ______ and ______.

Back 38

Mammary gland and teeth

Front 39

Short hair dogs have a _______ hair cycle, which leads to _______ hair loss.

Back 39

Shorter;

Frequent

Front 40

The cause of the damaged shortened hair cycle is ________, which also increases in aged people.

Back 40

FGF-5

Front 41

The _________ gland is associated with hair follicles.

Back 41

Sebaceous

Front 42

When sebaceous glands secrete sebum, secretory cells die and release all lipid droplets into the duct. This mode of secretion is:

Back 42

Holocrine

Front 43

_________ glands are most extensively developed in domestic animals and are simple tubular glands with a coiled secretory portion and a straight duct.

Back 43

Apocrine

Front 44

The duct of the ______ gland opens directly to skin surface, but frequently penetrates the epidermis of hair follicle just before the hair follicle opens onto the surface of the skin. Has myoepithelial cells between secretory cells and basal lamina.

Back 44

Aprocrine

Front 45

______ glands are mainly in areas like the nose and footpads. Are simple tubular mucous or serous.

Back 45

Merocrine (eccrine).

Most primates body contains merocrine sweat glands instead of apocrine glands like domestic animals.

Front 46

The two layers of the dermis are:

Back 46

1- Papillary dermis

2- Reticular dermis

Front 47

The ________ is made of the loose connective tissue that supports the epidermis. It contains type III collagen from reticular cells, and sometimes has dermal papillae (irregular projections).

Back 47

Papillary dermis

Front 48

The _________ is the thicker zone deeper beneath the epidermis. Has larger bundles of type I collagen and elastic fibers. Has arrector pili (smooth muscle near hair follicles) and mutations cause skin lesions (loose, thigh, fragile).

Back 48

Reticular dermis

Front 49

__________ are pressure receptors in the dermis. They are located deep in some skin and in joints, and are nerve fiber adapted. Function is sensory and they have nerves attached.

Back 49

Lamellar or Pacinian corpuscle

Front 50

_________ is present in the hypodermis

Back 50

Fat.

Front 51

Accumulation of _______ causes obesity.

Back 51

white adipocytes

Front 52

Loose and sagging skin is caused during the process of aging, because the body produces fewer new _________

Back 52

Elastic fibers.

Front 53

Connective tissue is ________

Back 53

everywhere

Front 54

There are 2 different types of cells of the connective tissue:

Back 54

1- Resident cells

2- Transient cells

Front 55

The 5 different types of resident cells are:

Back 55

1- Fibroblasts

2- Reticular cells

3- Adipocytes

4- Macrophages

5- Mast cells

Front 56

There are 5 types of transient cells:

Back 56

1- Plasma cells

2- Lymphocytes

3- Neutrophils

4- Basophils

5- Eosinophils

Front 57

_________ synthesize pro-collagen and matrix proteins, glycosaminoglycans. They are prominent in RER and Golgi. They repair CT (produce collagen)

Back 57

Fibroblassts

Front 58

______ cause fibrosis and scarring as a result of excessive collagen production. They are spindle shaped and have elongated cytoplasm.

Back 58

Fibroblasts

Front 59

_________ synthesize and release smaller collagen fibrils (type III collagen) and ground substance. They are mainly in bone marrow and lymph node, where they form stroma.

Back 59

Reticular cells

Front 60

___________ are derived from monocytes. They have indented/round nucleus, blue gray cytoplasm with vacuoles. Phagocytic cells. They process antigens for immune system.

Back 60

Macrophages

Front 61

Macrophages, histiocytes (anywhere), osteoclasts (bone marrow), Kupffer cells (liver), alveolar macrophages (lung) and microglial cells (brain).

Back 61

Mononuclear Phagocyte System (Reticuloendothelial system)

Front 62

__________ look like basophils, which are not normally in CT. They come from stem cells in bone marrow; basophil lineage. They are large basophilic granules that contain heparin, histamine, chemotactic factors, and proteases.

Back 62

Mast cells

Front 63

Histamine triggers inflammatory response (formation of edema) by increasing permeability of small blood vessels and proteases activate complement components in __________

Back 63

mast cells

Front 64

_______ stain so intense it can cover nucleus. Allergens cause release of granules. Also stain PAS+, but cannot recognize with eosin. Found under many epithelia.

Back 64

Mast cells

Front 65

_______ tumor. When this happens, the cells of the tumor are unstable. This means they release their toxic granules with simple contact or even at random, creating allergic symptoms that do not correlate with exposure to any particular antigen. They are notoriously invasive and difficult to treat.

Back 65

Mast cell

Front 66

______ are usually near loose CT. Can be white fat or brown fat.

Back 66

Adipocytes (fat cells)

Front 67

________ are larger cells and have less blood than brown.

Back 67

White fat

Front 68

______ are smaller cells, multilobular, vascularized. One of its most important functions is to warm up our blood.

Back 68

Brown fat. Looks brown because of there are so many mitochondria in them.

Front 69

________ migrate from blood vessels into the connective tissue at the site of infections. Migrate into the connective tissue by diapedesis.

Back 69

White blood cells

Front 70

There are 2 types of lymphocytes:

Back 70

1- T-cells

2- B-cells

Front 71

_______ have little cytoplasm, have heterochromatic nucleus, and are often seen intraepithelial.

Back 71

T-Cells

Front 72

_________ have a distinct cartwheel nucleus, have large basophilic cytoplasm, large Golgi, and sites susceptible to infection.

Back 72

B-Cells

Front 73

Terminally differentiated B-cells are ________, which produce antibodies

Back 73

plasma cells

Front 74

__________ have rounded nucleus and often foamy cytoplasm

Back 74

Monocytes -- macrophages

Front 75

__________ have segmented nucleus, respond to chemotaxis, are phagocytic -- destory anitgens, and appear in abcess or pus formation

Back 75

Neutrophils

Front 76

_________ have red granules (eosinophilic), nucleus with lobes, increased during allergies and parasites, and are phagocytic and stimulate collagen synthesis.

Back 76

Eosinophils

Front 77

The extracellular matrix of connective tissue is made of ______ and ________.

Back 77

Fibers and ground substance

Front 78

There are 2 types of fibers:

Back 78

1- Collagen

2- Elastin

Front 79

__________ is most abundant fiber and protein in body. 70% of skin, 90% of bone dry wt. It is flexible but strong, and there are over 10 types.

Back 79

Collagen

Front 80

The 4 important types of collagen are:

Back 80

Type I - skin, bone, tendon, ligament, dentine

Type II - cartilage

Type III - small fibers

Type IV - basement membrane

Front 81

________ forms when fibroblasts synthesize pro-collagen.

Back 81

Collagen

Front 82

RER to Golgi to microtubule path to secretion of rpocollagen to polymerization into fibril (15 nm) to grow into bundles. This is the formation of _____

Back 82

collagen

Front 83

Dermatosparaxis, Feline Cutaneous Asthenia (FCA), and Ehlers-Danlos Syndrome (EDS) in humans are _________

Back 83

collagen diseases

Front 84

________ is an inherited defect in collagen synthesis caused by deficiency of procollagen peptidase. Results in fragility, hyperelasticity, and laxity of the skin.

Back 84

Dermatosparaxis

Front 85

Type V collagen is incorrectly produced in cats with the autosomal dominant form of _______. This results in poor package of type I collagen. The autosomal recessive form of this is caused by deficiency of procollagen peptidase.

Back 85

Feline Cutaneous Asthenia

Front 86

_________ is caused by defects in synthesizing Type I or III collagen.

Back 86

Ehlers-Danlos Syndrome

Front 87

_______ are in some ligaments. Have no striation, are wavy. They stain light pink with H&E, and black with special stains.

Back 87

Elastic fibers

Front 88

_________ is the substance between cells and fibers

Back 88

Ground substance

Front 89

Ground substance is made of ________, huge molecules with more sugar content than protein content. Proteins attached to sugars.

Back 89

Proteoglycans

(NB: Glycoproteins: small molecules with greater protein content than sugar content. Sugars attached to protein)

Front 90

_________ are bottle brush-like. Hyaluronic acid is the backbone. It's function is water absorption and to provide flexibility and cushioning. The sugars are GAGs (glycosaminoglycans).

Back 90

Ground substance

Front 91

There are 5 different types of GAGs:

Back 91

1- Hyaluronic acid (most tissues, synovia, eye)

2- Chondroitin (cartilage)

3- Chondroitin sulfate (cartilage, bone)

4- Keratan sulfate (cartilage, bone)

5- Dermatan sulfate (skin)

Front 92

________ are negatively charged, therefore they attract Na+ ions and water by osmosis. This create gels (cushion) or impart resistance to compression to certain tissues.

Back 92

GAGs

GAGs in gels, lubricants attract lots of water, while GAGs in hard tissues (more sulfated) attract less water.

Front 93

__________ is the simplest of the GAGs. They are repeating disaccharide sequences forming huge chains. It is non sulfated.

Back 93

Hyaluronic acid (or hyaluonan)

Front 94

________ attract lots of water molecules, more than the other GAGs, and therefore make thick fluids or gels (synovial fluid contains almost only this). Plays a role in resisting compressive forces in tissues and joints.

Back 94

Hyaluronic acid

Front 95

_________ breed has abnormal hyaluronic acid synthesis. They make too much of it. Causes the wrinkled skin.

Back 95

Shar-Pei.

Front 96

_____________ is a sulfated GAG composed of a chain of alternating sulfated sugars. Usually found attached to proteins as part of a proteoglycan. It is an important structural component of cartilage and provides much of its resistance to compression.

Back 96

Chondroitin sulfate. (Hematoxylin stains sulfate groups blue to purple)

Front 97

_________ is areolar (much space) has high cellularity and Type I collagen fibers. It is located beneath epithelium, around blood vessels, around nerves, between muscle layers, and around fat.

Back 97

Loose Connective Tissue

Front 98

_________ has more fiber than cells, high amount of protein (type I collagen, stains pink by eosin), collagen bundles form weaves, and has fibroblasts. It is present in the dermis of skin, organ capsules, and beneath loose CT of major organs.

Back 98

Dense Irregular Connective Tissue

Front 99

__________ has fibers and the cells are parallel (string of pearls). It is located in tendons, ligaments, fibrous cartilage, and organ capsules. (Looks like thick smooth muscle bundles)

Back 99

Dense Regular Connective Tissue