Human Biology Test Review

Epidermis

Keratinized stratified squamous epithelium

Dermis

Underlying CT
w/ Papillary & Reticular Layer

Papillary Layer

Areolar CT

Reticular Layer

Dense Irregular CT

Hypodermis

Adipose

Accessory Organs

Hair & Hair Follicles
Glands

Sudoriferous Glands

secrete sweat

Sebaceous Glands

secrete oil (sebum)

Histology of Epidermis

Keratinocytes
Melanocytes
Langerhan's Cells
Merkel Cells

Keratinocytes

Filled w/ keratin
surrounded by glycolipids
tightly connected by desmosomes
always being formed, move up, die, fall off
lifespan 25-40 days

Human Defensin

secreted by keratinocytes
pokes holes in bacteria

Melanocytes

cells w/ long thin projections
form melanosomes(to keratinocytes)
form shield around nuclei surface

Langerhan's cells

long thin projections
macrophages consume foreign material & present to lymphocytes(immune)

Merkel cells

Epidermal side of basement membrane
Sensory nerve ending on dermal side of basement membrane
Sense pressure & Texture

Layers of Epidermis

Stratum Basale
Stratum Spinosum
Stratum Granulosum
Stratum Licudum
Stratum Corneum

Stratum Basale

Deepest, 1 cell thick, actively dividing
Melanocytes & Merkel cells

Stratum Spinosum

Several layers of keratinocytes
cells contain pre-keratin protein
Langerhan's cells

Stratum Granulosum
-cells toughen up

3-5 cell layers
cells flatten & fill w/ keratin
secrete glycolipids (waterproof)
membrane thickens w/ protein

Stratum Lucidum

thin clear layer
only thick skin

Stratum Corneum

20-30 dead cell layers
resistant to bio., chem. & mech. assault

Cells of Dermis

fibroblasts, macrophages, mast cells & WBC

Matrix of Dermis

Collagen, elastin & reticular fibers
-binds body together

Histology of Dermis
-Sense/Transport

Nerve fibers & sensory receptors
Blood & lymphatic vessels

Papillary layer of Dermis

Areolar CT (fill dermal papilla)
holds skin layers together
ridges on hands & feet increase function

Reticular layer of Dermis

Dense Irregular CT
lines of cleavage -less dense regions in planes // to surface
flexure lines

Eccrine Glands

Sweat, 99% water
slightly acidic
contains antibodies & some metabolic wastes
Function - prevent overheating

Apocrine Glands

Sweat glands in axillary & anogenital areas
more fatty substances & proteins
begin @ puberty
organics compose --> body odor

Ceruminous Glands

modified apocrine glands
secrete wax in ears

Mammary Glands

modified sweat gland
produces milk

Function of Sebaceous Glands

Soften/lubricate hair
Decrease water loss
some lipids inhibit growth of gram+ bacteria

Parts of Hair

Shaft & Root
Medulla, Cortex & Cuticle (Epidermal cells)
Matrix(active divide cells in root bulb)
Melanocytes

Parts of Hair Follicle

Internal root sheath & external root sheath (epidermal cells), glassy membrae & CT sheath
Hair Papilla (like dermal pap. w/ capillary plexus)
Sebaceous Gland
Arrector pili muscle (goose bumps)
Root Hair Plexus

Function of Body Hair

Sense insects

Function of Scalp Hair

Protect from physical trauma, heat loss & sunlight

Function of Eyelashes

Sunlight

Nose Hairs

Filters

Terminal Hairs

Coarse & grow in response 2 androgens

Vellus Hairs

Fine body hairs of kids & adult females

each follicle has a cycle of a ...

Growth Phase &
Resting Phase

Thermoreceptors in skin

detect changes in body temp.

Control Center
(temp control)

Hypothalamus in brain

Effectors
(temp control)

sweat glands, blood vessels, muscle cells & metabolism

Responses to cool body
(temp control)

sweat, vasodilation, slow metabolic rate & decreased muscle contraction

Responses to warm body
(temp control)

vasoconstriction of dermis/blood vessels & shivering

Types of Cancer
3

Basal Cell Carcinoma
Squamous Cell Carcinoma
Melanoma

Basal Cell Carcinoma

Least Maligents, Most Common
Cells invade underlying layers
Slow growing
usually identified/excises prior to metastisis

Squamous Cell Carinoma

Keratinocytes of stratum spinosum
Scaly reddish papule
Grows rapidly & metastasizes if not removed

Melanoma

Melanocytes
Most dangerous, on 5% all skin cancers
Spreading brown/black patch
metastasizes rapidly to surround lymph & blood vessels

Malignant

Cancer
spread, invade near tissues/blood vessels & metastasize
Bad 'Mal'

Benign

Not Cancer
local, not spread
Good 'Bien'

Burns

Tissue Damage caused by heat, elec., radiation or chem.

Medical Concerns
of Burns

Fluid loss --> renal shutdown
Extra calories via IV
>24 hours = infection
Immune System deficient w/n 2 days

1st Degree Burn

Epidermal Damage only
heals w/n 2-3 days

2nd Degree Burn

Epidermal & superficial dermis
blistering
heals w/n 3-4 weeks

3rd Degree Burn

entire skin thickness
must repair w/ a graft

Critical Burns

>25% - 2nd Degree
>10% - 3rd Degree
3rd Degree on face/hands/feet

Tumor
(Neoplasms)

Uncontrolled Cell Division

Hyperplasia

Faster than normal cell division & growth

Dysplasia

Abnormal formation of cells

Carcinoma in Situ

severe dysplasia

Proto-Oncogenes

Normal cell growth

Oncogenes

Cancer cell growth

Tumor Suppressor Genes

act like brake pedal in cell division

p53

Tumor Suppressor Protein
Triggers cell suicide
'emo cell'

mutagen

mutate DNA in genes

carcinogen

cause cancer

change in DNA sequence

mutation

carcinoma

true cancer
involve epithelial tissue

leukemia

WBC cancer

lymphoma

lymph cell cancer

sarcoma

CT & muscle cancer

acute

serious/immediate
cancer

synergy

2 factors that multiply effect
sum>parts

Histology

Study of tissues

tissue

group of similar cells that work together to perform a specific function

Types of Tissues

Epithelial
Connective
Muscular
Nervous

Epithelial Tissue
2 types

Membranous (covering/lining)
& Glandular

Features of Epithelium

Closely packed
Continuous sheets, single/multi.
Polarity(Apical/Basal surface)
Avascular
Support by CT = reticular lamina
Basement membrane
Nerve supply
Wear & tear

Avascular

no blood supply

Basement Membrane

layer of material that separates epithelium from CT

Classification of Epithelium

Cell Shape
-Squamous, Cuboidal, Columnar, Transitional(stretchy)
Layers
-Simple, Pseudostratified, Stratified

Simple Squamous Epithelium

Diffusion & Filtration
Found in alveoli, <3 lining, blood vessels, lymphatic vessels
line ventral body cavity
Endothelium(lines vessels lumen)
Mesothelium(lines serous membranes)

Simple Cuboidal Epithelium

Secretion & Absorption
Found in lining ducts & tubules of secrete/absorb.(kidneys, salivary glands, pancreas)

Simple Columnar Epithelium

Absorption
Secrete mucous(Goblet cells), enzymes or other substances
Cilia moves mucous & reproduct. cells
Non cilia forms microvilli(no move, absorb)

Pseudostratified Columnar Epithelium

some don't reach apical surface
many contain goblet/cilia
lumen of trachea, bronchial tubes, sperm ducts

Stratified Squamous Epithelium

Constant. divide basal layer
Cells dehydrate/flatten as move towards apical surface
Apical surface sloughed off
Function protect deeper layers
Keratinized stratified squamous - skin
Nonkeratinized stratified squamous - mucosa
Oral cavity, pharynx, nasal cavity, vag, anal canal

Stratified Columnar Epithelium

Uncommon
Function in secretion/protection
Male urethra & large ducts of some glands

Transitional Epithelium

Allow tissue 2 stretch
Only in urinary tract-bladder

Glandular Epithelium

Endrocrine Glands
-Ductless, secrete into ECF, produce hormones
Exocrine Glands
-Secrete product onto apical surface of membranous epithelium & secrete mucous, sweat, oil, wax, digestive enzymes

Epithelial Membranes

-Epithelium, basement membrane, underlying CT proper(loose or dense CT)
-Describes location of epithelium in body
-3 types, Cutaneous, Serous & Mucous Membranes

Cutaneous Membranes

Skin (air exposure)
Keratinized stratified squamous epithelium + dense irregular CT
Only dry membrane

Serous Membranes

line ventral body cavity
simple squamous(mesothelium) + areolar CT
Secretes serous fluid rich in hyaluronic fluid(lubricates surfaces of body cavities)

Mucous Membranes

Wet Membrane
Line passageways to exterior
Usually stratified squamous or variety of columnar epithelium + loose CT called 'lamina propria'

Muscle Tissue

Function : Contraction
3 Types:
Skeletal/striated (voluntary)
Visceral/smooth
Cardiac (involuntary)

Nervous Tissue

Function: Communication
Cells -
Neurons (info)
Neuroglial (supporting) cells

Tissue Repair
Homeostatis

Regeneration(replacement of destroyed tissues w/ same tissue)
&
Fibrosis formation(scar)-replacement w/ fibrous CT

3 Steps to Skin Repair

Inflammation
Organization
Permanent Repair

Inflammation
Step 1

WBC release inflammatory chem. that increase blood supply & permeability of vessels, more cells migrate from blood 2 injured site
Clotting factors seal damaged blood vessels

Organization
Step 2

Blood clot replaced by granulation tissue(fibroblasts/capillaries)
Macrophages consume cellular debris & pathogens

Permanent Repair

Epithelium Regenerates
Scab Detaches
Scar tissue remains

Connective Tissue

Most abundant tissue type

Function of CT

Binds together, supports & strengthens other body tissues
Protects & insulates internal organs
Compartmentalizes structures
Transports substances

Types of CT

Connective tissue proper(fat, fibrous CT)
Cartilage
Bone
Blood

General Features of CT

All derived from embryonic mesenchyme(simple)
Vascularized, (but varies)
Composed of matric & cells
-Matrix(ECM) =ground substance & protein fibers

Ground Substances
CT Matrix

Fills space b/w cells, contains fibers
Composed of Interstitial fluid (ECF), cell adhesion proteins and proteoglycans (protein +carbohydrate/glycosaminoglycans)
Acts as molecular sieve though dissolved nutrients & wastes diffuse

Fibers
3 types

Collagen Fibers
Elastic Fibers
Reticular Fibers

Collagen Fibers

Rope/cable-no stretch
Strength
Resistant to pulling, yet flexible

Elastic Fibers

Smaller than collagen(thinner)
Contain elastin
Provide strength & elasticity
In skin, blood vessels & lungs
Can stretch be spiral

Reticular Fibers

Fine collagenous proteins
Continuous w/ collagen fibers
Branch from collagen fibers forming networks (reticula=network)
Support for walls of blood vessels, nerve fibers, skeletal & smooth muscle(anchors ground substances, keep in place)

Cells found in CT

Immature cells -blast, mitotic & secrete matrix
-Fibroblasts (CT Proper)
-Chondroblasts (cartilage)
-Osteoblasts (bone)
-Hematopoietic stem cells (blood)
Mature Cells - cyte, less active (done dividing, ready)

Other Cells

Fat Cells
WBC include:
-Mast calls --> Heparine, histamine, proteases
-Macrophages --> phagocytosis
-Plasma Cells --> antibiodies

Anti-histomines

reduce swelling by dialating blood vessels, open gaps, more fluid flow

Mesenchyme

Embryonic
Develops into all other forms of CT
Mucous CT (jellylike, only found in umbilical cord)

Loose CT

Fibers loosely arranged
Many cells
3 Types:
-Areolar CT, Adipose, Reticular CT

Areolar CT

Gel-like, all 3 fibers, fluid mostly hyaluronic acid
Fiber irregular(all directions)
Many cells(fibroblasts, macrophages, plasma cells, mast cells)
Surrounds organs, capillaries, muscle fibers & groups(fascias), part of subcutaneous layer of skin
Edema-mast cells-->histamine-->blood vessels leak

Adipose

Similar to areolar but most cells adipocytes
Triglycerides fill most of adipocytes
Highly vascularized
Normally 18% of body weight
Stores energy, insulates, cushions

Reticular CT

Similar to areolar but reticular fibers are only fibers present
Fine reticular fibers interlace & cells interlace w/n a jellylike matrix
forms stroma(meat/framework) of many organs(liver, lymphnodes, bonemarrow)
Binds together cells of smooth muscles

Dense CT

Fibers more numerous#, thicker & dense
Includes:
-Dense Regular CT(Elastic CT)
-Dense Irregular CT

Dense Regular CT

Bundles of Collagen fibers
Regular & // arrangment
Resists pulling, but flexible
Found in tendons, ligaments & aponeuroses

Elastic CT

Basicaly Dense Regular CT, but w/ a lot of elastic fibers that allow stretching 50% of normal length
Walls of large arteries, portion of larynx, trachea & bronchial tubes

Dense Irregular CT

Collagen fibers irregularly arranged --> strength in many directions
In Dermis, submucosa of GI tract, capsules of organs & joints

Cartilage

More stree than other tissues
No nerves, avascular
Dense network of collagen & elastc fibers surrounded by chonroitin sulfate (strength)-ground substances
Chondrocytes - found in lacunaw(lagoon)
Nutrients must diffuse via matrix
Repair is slow

Hyaline Cartilage

Collagen fibers not visible
Ground substance also contians hyaluronic acid(reduce friction)
Trachae, bronchi, nose w/e ribs & sternum, articulations of bones
Flexible & supportive, reduces friction & shock

Fibrocartilage

Collagen fibers visible
Strong & rigid
Pubic symphysis & b/w vertebrae

Elastic Cartilage

Contains elastic fibers
Pinnae, parts of larynx, auditory canal

Bone (Osseous) Tissue

Osteoblasts secrete collagen fibers, followed by calcium salts
Mature Osteocytes reside in lacunae surrounded by layers of bony matrix
Nerve supply & vascularized

Blood(Vascular) Tissue

Matrix is plasma(ground substance mostly H20 & fibers dissolved proteins)
Cells include RBC, WBC & platelets