Tissues and Integument

Name the four types of tissues and their general function

Name the four types of tissues and their general function

1. Muscular (movement)

2. Epithelial (covering/lining)

3. Nervous (control)

4. Connective (support)

How is epithelial tissue classified

CELL LAYERS -Simple, stratified, pseudostratified

SHAPE -Squamous, cuboidal, columnar

Is epithelial tissue vascular or avascular

Avascular, lack of blood vessels

What are the three surfaces of epithelial cells

Apical - upper part of cell, exposed to outside of body/the cavity its lining Lateral - side of cell Basal - attached to basement membrane (made up of mostly collagen) which holds cell and attaches it to connective tissues

What does it mean if an epithelial tissue cell is pseudostratified

Looks like it has multiple layers, but only has one

What are some characteristic of connective tissue

-most abundant by weight -usually well vascularized

What are some functions of connective tissue

• binding and support (produces structural proteins like elastin and collagen)

-protection against infection (blood is a connective tissue - WBC)

-Tissue repair (any vascularized tissue is capable of self repair as it easily rcvs nutrients, that's how bones repair themselves)

-Insultation - fat is a connective tissue

What are connective tissue cells surrounded by

ECM = extra cellular matrix

What is the extra cellular matrix of connective tissue composed of

Ground substance + fibers (collagen/elastin, etc)

What are the 4 properties of ground substance

Fluid, semi-fluid, gelatinous, or calcified

What are the four classes of connective tissue

1 Connective tissue proper (loose and dense) 2 Cartilage 3 Bone 4 Blood

What is the predominant cell type in Bone tissue + its ground substance

Osteocytes (calcified GS)

What is the predominant cell type in Connective tissue proper LOOSE + its ground substance

Adipocytes (semi fluid GS)

What is the predominant cell type in Cartilage tissue + its ground substance

Chondrocytes (gelatinous GS)

What is the predominant cell type in Blood tissue + its ground substance

Red blood cells/erythrocytes (fluid GS)

What is the predominant cell type in Connective tissue proper DENSE + its ground substance

Fibroblasts (not a lot of GS)

What are some examples of how skin can be an indicator of disease

Colour of the skin can indicate clinical conditions:

Cyanotic (blue) - lack of blood oxygen (hypoxemia)

Jaundiced/Icteric (yellow) - Liver dysfunction - buildup of bilirubin waste, when RBC get old and must be removed from bloodstream and broken down in the liver, one aspect of hemoglobin remains and is extracted thru liver --> GI tract (liver issue = bilirubin can't get out)

Erythema (red) - Heat infection, allergic rxn (blood travels to where it needs to heal)

Pallor (white) - shock (loss of blood) Anemia (not making enough RBC) Peripheral vasoconstriction (when body is too cold, it diverts blood away from skin to heat core temp)

What are the layers of the skin

Epidermis + dermis which sit on the Hypodermis (SQ layer below the cutaneous skin)

Name the 5 strata of the Epidermis

(highest to lowest) Corneum (horny layer) Lucidum (only in thick skin) Granulosum (living dead layer) Spinosum (spiny) Basale (germinativum)

Acronym : C(come) L(lets) G(get) S(sun) B(burned)

To remember the strata of the epidermis Corneum, Lucidum, Granulosum, Spinosum, Basale

What stratum is present in thick skin but not in thin skin

Lucidum (only found in the soles of your feet and palms of your hands)

What are the 4 cell types of the Epidermis

Keratinocytes (produces keratin, most prominent cell)

Langerhans (found in stratum SPINOSUM, immune cells)

Melanocyte (Found in stratum BASALE w spindles that deposit melanin in stratum spinosum, protects Keratin against UV rays)

Merkel (detects fine touch, found in stratum BASALE)

What is the role of Keratin

Provide protection against heat Protects against external abrasion Barrier to microbes (as there are no breaks b/w cells)

What is the significance of epidermal ridges

Improves your grip and increases surface area of epidermis

Internal epidermal pegs + dermal papillas increase contact b/w dermis and epidermis (like a zipper)

What is the purpose of melanin and what produces it

Protect keratin/the germinal layer against UV rays Produced by melanocytes (we all have the name # of these but they produce diff amts of melanin in each person)

What are the 2 types of melanin

Pheomelanin (yellow/red hue) Eumelanin (brown/black hue)

Why does tanning darken your skin?

Dna in Keratinocytes start to become damaged/denatured due to increased UV rays --> produces melanocyte stimulating hormone --> tells melanocytes to start producing more melanin --> skin darkens

What is skin tone an expression of

3 pigments

1. Melanin (mostly this) - yellow/red + brown/black

2. Carotene (vitamin a) - yellow/orange

3. Hemoglobin (in blood) - red

List some examples of melanocyte alterations

• ALBINISM - no melanin produced (production off due to mutation)

• FRECKLES - concentrations of melanocytes produce a lot of melanin in certain areas

• VITILIGO - autoimmune disorder (adapted immune cells see melanocytes as foreign bodies)

• MELANOMA - cancerous moles (developed from benign nevi/moles)

What are the features of Benign Nevi vs Malignant Melanomas

ABCDE of malignant melanoma asymmetry, border (irregular), colour, diameter, evolving

Nevi/moles (benign) are symmetrical, have regular circular borders, are one colour, diameter less than 6mm, and not changing

What is the structure and function of the dermis

-deeper than epidermis

-binds epidermis to underlying tissues (hypodermis, which sits on skeletal muscle attached to the skeleton)

-had abundance of collagen/elastin (secreted by fibroblasts) to support skin

-is the location of blood vessels, nerves, hair follicles, and skin glands

-divide into papillary region (superficial), and reticular region (deep)

What are the four main skin glands of the dermis

1. Sebaceous (produces oil, sits on hair follicles)

2. Apocrine (also on hair follicles, watery secretion, found in armpits/pubic region)

3. Eccrine (makes swear, regulated by sympatic nervous sytm)

4. Ceruminous (earwax, prevents foreign bodies (bugs) in ears)

What is the primary cell type of the dermis

Fibroblasts

Name the 6 functions of the skin

• Temp regulation

• blood reservoir

• protects from environment

• cutaneous sensations

• secretion and absorption

• metabolism

How does skin play a role in metabolism

contributes to vitamin D synthesis (which is needed to absorb calcium in diet)

What waste products are secreted in sweat

ammonia and urea