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384 Cards in this Set

  • Front
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Define tissue.
Group of similar cells that work together towards a certain function.
Define histology.
Study of tissues
Four types of tissue
1) Epithelial
2) Connective
3) Muscle
4) Nervous
Two types of epithelial tissue
1) Membranous Epithelia (sheet-like)
2) Glandular Epithelia (secrete stuff)
3 types of cells in membranous epithelia
1) Squamous
2) Cuboidal
3) Columnar
Simple Squamous Epithelia makes up...?
-Make up part of the filtration membrane in kidneys, respiratory membrane in the lungs, and serous membrane
Mesothelium
Simple squamous epithelia in the serous membrane (that lines the ventral body cavity)
Endothelium
Simple squamous epithelia in the central nervous system
Functions of simple squamous epithelia
Filters
Diffuses
Secretes lubricants (to reduce friction)
Properties of Epithelial tissue
-Cells form tight junctions and desmosomes
-Has polarity
-Apical (top) surface has microvilli/cilia
-On top of the basement membrane
-Supported by CT underneath reticular layer
-Avascular
-Gets nutrients from CT
-Integrated (has nerve fibers)
-Can regenerate easily
Basement membrane is composed of...?
Has a basal lamina layer on top of the reticular lamina layer
Basal Lamina
-Sticky sublayer made of glycoproteins right under the basal layer
-Has no cells
-Functions as a selective filter
Reticular Lamina
-Under the basal lamina and above the CT
-Made of collagen fibers
-Supports epithelial tissue and is the bottom boundary of ET
Properties of Simple Cuboidal Epithelia
-In tubules of kidneys
-In surface of ovaries
-Absorbs & secretes
Simple Cuboidal Epithelia located in the surface of ovaries is called....?
Germinal Epithelium
Properties of Nonciliated Simple Columnar Epithelia (SCE)
-Lines the GI tract
-Microvilli and goblet cells are in the SCE cells
-Secretion and absorption
What do Goblet cells secrete?
Goblet cells secrete a mucoglycoprotein called mucin
Properties of Ciliated Simple Columnar Epithelia (SCE)
-In uterine tubes (Fallopian tubes)
-Cilia beats to move the conceptus, ova or zygote
Properties of Ciliated Pseudostratified Columnar Epithelium
-Lines most of the structures of the respiratory system
-Has goblet cells & secretes mucus
-Cilia beat to trap excesses in respiratory passages
What is another name for Ciliated Pseudostratified Columnar Epithelium?
Respiratory Epithelium
Properties of Nonciliated Pseudostratified Columnar Epithelium
-In males, sperm carrying duct system
-Involved in absorption, phagocytosis of old sperm and limited protection
What is the name of the duct system that carries sperm from the testes to the outside in Nonciliated Pseudostratified Columnar Epithelium?
Epididymides vasa diferentia urethra
Stratified Epithelium all have ____ of cells
Stratified epithelium all have more than 1 layer of cells.
What are the 6 types of membranous epithelia?
1) Simple Squamous Epithelia
2) Simple Cuboidal Epithelia
3) Nonciliated Simple Columnar Epithelia
4) Ciliated Simple Columnar Epithelia
5) Ciliated Pseudostratified Columnar Epithelium
6) Nonciliated Pseudostratified Columnar Epithelium
Stratified squamous epithelium has flat cells on the ____ layer or ____ surface.
Stratified squamous epithelium has flat cells on the top layer (or apical surface).
2 types of stratified squamous epithelium
1) Keratinized
2) Nonkeratinized
Properties of Keratinized stratified squamous epithelium
-In epidermis
-On top layers, keratin is grown in keratinized cells
-Provides ultimate protection (abrasive-resistant)
Properties of Nonkeratinized stratified squamous epithelium
-In openings of body tracts (GI, reproductive, respiratory and urinary)
-Protects
Properties of Stratified Columnar Epithelium
-Columnar cells on top layer
-In ducts of glands: mammary glands and lower part of male urethra
-Secretes and protects
Properties of Stratified Cuboidal Epithelium
-Cuboidal cells on top layer
-Lines ducts of glands (salivary glands)
-Secretes and protects
Properties of Transitional Epithelium
-3 or 6 layers of cells
-Top layer has flattened or cuboidal cells
-Lines ureters and bladder (in urinary system)
What happens to transitional epithelium when urinary structures fill?
The top layer changes from 6 layers of cuboidal cells to 3 layers of squamous cells.
Properties of Glandular Epithelium
Epithelial cells form glands that secrete substances
Endocrine Gland
Ductless gland that secretes hormones into extracellular fluid (blood and interstitial fluid)
Exocrine Gland
Secretes substances to surface of body or into body cavities
5 types of stratified epithelium
1) Stratified Squamous Epithelium
2) Stratified Columnar Epithelium
3) Stratified Cuboidal Epithelium
4) Transitional Epithelium
5) Glandular Epithelium
What are the 3 modes of secretion for multicellular exocrine cells?
1) Apocrine
2) Merocrine
3) Holocrine
Apocrine mode of secretion
-Substance builds uder the top surface of secretory cells
-Cells apex is pinched off to rrelease substance into duct
-Example: Secreting fat into breast milk through mammary glands
Merocrine mode of secretion
Substance released from secretory cells by exocytosis
Holocrine mode of secretion
Substance builds in the secretory cells until they break, releasing the substance
Properties of Connective Tissue
-Most abundant type of primary tissue
-Can be avascular, poorly vascularized, or highly vascularized
-Comes from mesenchyme
Connective tissue in cartilage is _______.
Connective tissue in cartilage is avascular.
Connective tissue in dense regular tissue is ______.
Connective tissue in dense regular tissue is poorly vascularized.
Connective tissue in dense irregular tissue is _____.
Connective tissue in dense irregular tissue is highly vascularized.
Where does all connective tissue come from?
Mesenchyme (embryonic connective tissue)
What are the 3 types of fibers?
1) Collagen fibers
2) Elastic fibers
3) Reticular fibers
Properties of Elastic Fibers
-Composed of the protein elastin
-Stretch recoil property
-"Yellow fibers"
What is the stretch recoil property?
Ability of elastic fibers to stretch to accomodate pressure and recoil to their original size when pressure is removed
Why are elastic fibers called "yellow fibers"?
In freshly prepared slides, the elastic fibers appear yellowish
Properties of Reticular Fibers
Composed of fine, collagen-like fibers that branch extensively to form networks
What are the four classes of connective tissue (based on the four types of connective tissue cells)?
1) Fibroblasts
2) Chondroblasts
3) Osteoblasts
4) Hematopoietic stem cells
What do Fibroblasts secrete?
Connective tissue proper
What do Chondroblasts give rise to?
Cartilage
What do Osteoblasts give rise to?
Bone tissue
What do Hematopoietic stem cells give rise to?
Blood cells
What is the predominant cell type in CT Proper?
Fibroblasts
What is the consistency of the ground substance for CT Proper?
Gel-like
What are 2 subclasses of CT Proper?
1) Loose
2) Dense
What are the 3 types of Loose CT?
1) Areolar CT
2) Adipose CT
3) Reticular CT
What does areolar CT do?
Supports epithelial tissues
What does areolar CT form?
Lamina Propria and Subcutaneous Layer
Lamina Propria
Areolar CT that supports the epithelial tissue lining the tracks of the body
Epithelial tissue with lamina propria is also known as...?
Mucous membrane
Subcutaneous Layer
Areolar CT that forms the fascia which supports structures and organs; Absorbs and holds the interstitial fluid
What are the functions of Areolar CT?
-Support of avascular tissue by giving overlying epithelial tissue nutrients
-Wraps around organs for protection
-Can be involved in fighting infection
What is areolar CT also referred to as due to its support and wrapping functions?
The "packing material of the body"
If immune cells, such as macrophages, are present in the areolar CT, then this tissue is involved in ____.
If immune cells, such as macrophages are present in the areolar CT, then this tissue is involved in fighting infection.
Location of Adipose CT
Around organs and in the subcutaneous layer supporting the skin
Function of Adipose CT
Cells of the adipose tissue (adipocytes) are filled with triglycerides to provide:
-Protection to surrounding organs
-Energy production
-Insulation
-Protection against trauma; acts as a shock absorber
____ is/are the most concentrated form of stored energy.
Triglycerides (fat) are/is the most concentrated form of stored energy
Reticular CT is secreted by _____.
Reticular CT is secreted by Fibroblasts called Reticular Cells.
Fiber type of Reticular CT
Reticular fibers
Reticular fibers of Reticular CT form ___.
Reticular fibers of Reticular CT form networks inside lymphoid organs such as the spleen and lymph nodes.
Function of Reticular CT inside lymphoid organs
Supports the immune cells
Cell type of Dense Connective Tissue
Fibroblasts
What is the consistency of the ground substance of Dense CT?
Gel-like
What is Dense CT mostly made up of?
Collagen Fibers
What is Dense CT also referred to as?
"Fibrous CT" because it is made up of mostly collagen fibers
3 Types of Dense CT
1) Dense Regular CT
2) Dense Irregular CT
3) Elastic CT
Dense Regular CT
Thick bundles of collagen in parallel rows to the direction of force
Location(s) of Dense Regular CT
-Tendons
-Aponeurosis
-Ligaments
Properties of Dense Regular CT
-Poorly vascularized
-May form capsules around structures
Function of Dense Regular CT
Provides high tensile strength to withstand mechanical forces placed on the structures it supports
Dense Irregular CT
Thicker bundles of collagen fibers arranged in an irregular fashion (collagen fibers run in all directions).
Dense Irregular CT is poorly or highly vascularized?
Dense Irregular CT is HIGHLY vascularized.
Location(s) of Dense Irregular CT
-Reticular layer of the dermis
-Surrounds bone (periosteum)
-Surrounds cartilage (periochondrium)
Function(s) of Dense Irregular CT
-Allows for structures to withstand mechanical forces applied in different directions
-Provides nutrients to the structures it surrounds and the epidermis
Elastic CT
Bundles of elastic (high levels) and some collagen fibers arranged in parallel rows.
Location of Elastic CT
In between vertebrae (ligamentum flavum)
Function of Elastic CT
Allows for the vertebral column to be stretched under pressure (bending forward) and recoiled when pressure is removed (standing upright).
Cell type secreted by Cartilage
Chondroblasts
Consistency of the ground substance of Cartilage
Semi-solid
Why is the ground substance of Cartilage semi-solid in consistency?
Due to the increased numbers of GAGs (increased chondroitin sulfate and increased hyaluronic acid)
Is cartilage: avascular, poorly vascularized or highly vascularized?
Cartilage is avascular.
From where does cartilage receive its nutrients?
The perichondrium surrounding it
Types of Cartilage
1) Hyaline Cartilage
2) Fibrocartilage
Properties of Hyaline Cartilage
-Blue-white in color and glossy
-Chondrocytes stay in lacunae
-Can be stiff and/or flexible
What does Hyaline Cartilage form?
-Embryonic skeleton
-Articular cartilage (at the end of long bones)
-Epiphyseal plates (where diaphysis & epiphysis meet)
-Costal cartilage (connects ribs to sternum)
-Alar cartilage (outside of nose)
Properties of Fibrocartilage
-Made of groups of collagen fibers and rows of chondroblasts/chondrocytes
-Prevents wear and tear by fitting bones together
What does Fibrocartilage form?
-Intervertebral discs
-Mensici (pads between bones at synovial joint)
-Pubic symphysis (connects oscoxae -- hips)
Function(s) of Fibrocartilage
-Prevents wear and tear by fitting bones together
-Shock absorber
Bone is a type of ____ tissue.
Bone is a type of connective tissue.
Cartilage is a type of ___ tissue.
Cartilage is a type of connective tissue.
What is Bone also referred to as?
"Osseous tissue"
What cell type makes up Bone Tissue?
Osteoblasts
What is the consistency of the ground substance for Bone Tissue?
Solid
What are the 2 parts of Bone Tissue?
1) Living (osteoblasts)
2) Nonliving (extracellular matrix)
Extracellular Matrix of Bone Tissue has two regions... What are they?
1) Organic (Osteoid)
2) Inorganic
What is the Organic region of the Extracellular Matrix of Bone Tissue made of?
Solid ground substance and mostly collagen fiber
What is the Inorganic region of the Extracellular Matrix of Bone Tissue made of?
Has Hydroxyappetites (calcium phosphate - salt crystal)
Hard ground substance due to gas and hydroxyappetites
What are the 2 types of Bone Tissue?
1) Compact (dense)
2) Spongy
What are the 4 types of Connective tissue?
1) Connective Tissue Proper
2) Cartilage
3) Bone Tissue
4) Blood
What is Compact (dense) Bone Tissue made of?
Osteons
What is Spongy Bone Tissue made of?
Trabeculae in a honeycomb-like form
Functions of Bone Tissue
-Form part of bones (as organs)
-Protect organs
-Support
-Levers for movement
-Make blood cells (through the process called hematopoiesis)
Where does hematopoiesis occur?
In red bone marrow in spongy tissue of bones or in the medullary cavity
_______ in red bone marrow make blood.
Hematopoietic stem cells in red bone marrow make blood.
What is the consistency of the ground substance for Blood?
Fluid
Where is Blood located?
In blood vessels
What is the function of Blood?
Transport of gases, nutrients, wastes, hormones and immune cells
What is Plasma?
Fluid matrix in a blood cell
What is Fibrinogen?
Main fiber in blood (soluble protein)
What is Coagulation?
Blood clot formation
During coagulation, fibrinogen is made into ____.
During coagulation, fibrinogen is made into fibrin (insoluble form).
What are the 4 types of membranes?
1) Cutaneous Membrane (skin)
2) Mucous Membrane
3) Serous Membrane
4) Synovial Membrane
Top and bottom tissues of the Cutaneous Membrane
Top: Keratinized stratified squamous epithelial tissue
Bottom: Dense irregular CT
Top and bottom tissues of the Mucous Membrane
Top: Nonkeratinized stratified squamous or simple columnar epithelial tissue
Bottom: Areolar CT
Location of Mucous Membrane
Lines the body tracts
Location of Serous Membrane
Lines structures in Ventral Body Cavity
Top and bottom tissues of the Serous Membrane
Top: Mesothelium (Simple squamous epithelial tissue)
Bottom: Areolar CT
Top and Bottom tissues of the Synovial Membrane
Top: Areolar CT
Bottom: Dense Irregular CT
3 Types of Muscle Tissue
1) Skeletal MT
2) Cardiac MT
3) Smooth MT
Properties of Muscle Tissue (in general)
-Highly vascularized
-Made up of a lot of closely packed cells (cellular)
Properties of Skeletal Muscle Tissue
-Long cylindrical cells (muscle fibers)
-Striated
-Multinucleated cells
-Contracts with voluntary control
Skeletal muscle (as an organ) is made of ....?
-Skeletal MT
-Connective Tissue
-Blood vessels
-Nerve fibers
Skeletal muscle attaches ____ and _____.
Skeletal muscle attaches bone and skin.
What makes skeletal MT cells striated?
Alternating actin and myosin (contractile proteins in the muscle cell)
Properties of Cardiac Muscle Tissue
-Uninucleated cells
-Striated cells
-Contracts to move blood through vessels/vasculature
-Involuntary control
What is Cardiac MT made of?
Highly branching cells that interlock (interdigitate) to form membrane junctions (intercalated discs)
What are the intercalated discs of Cardiac MT made of?
Desmosomes and gap junctions
Where is Cardiac MT located?
In myocardium - the middle layer of the hard wall
Properties of Smooth Muscle Tissue
-Spindle shaped cells
-Uninucleated
-No striations (smooth)
-Forms sheets in middle layer of walls in tracts (i.e.,GI tracts)
-Contracts to move substances down the tract
-Involuntary control
Nervous tissue is ____ cellular.
Nervous tissue is highly cellular.
2 cell types that compose Nervous Tissue
1) Neurons
2) Neuroglia (supporting cells)
Neuroglia
Non-conducting cells in the nervous tissue which support, protect, and nourish the neurons
Neurons
Branching cells that generate and transmit electrical signals
Properties of Neurons
-Exhibit longevity
-Amitotic
-Very high metabolic rate
-Catabolize (break down) glucose in the presence of oxygen
Neurons require a constant supply of _____.
Neurons require a constant supply of oxygen.
Why are neurons amitotic?
Neurons cannot under mitosis because neurons lack centrosomes and hence centrioles (which mitotic spindles cannot be made without)
What are the structural features of Neurons?
-Cell body
-Nissil bodies
-Mitochondria & Golgi present
-Centrosome absent
-Dendrites
-Axon
Because protein synthesis occurs in the cell body, it is also known as ...?
The biosynthetic center (biosynthetic region of a neuron)
What does the cell body contain?
The nucleus with a prominent nucleolus
Nissil Bodies (Chromatophillic substances)
Specialized rough ER located in a neuron
Dendrites
-Extend from the cell body
-Receive electrical signals coming from the neuron
Dendrites are also known as...?
Receptive region
Axon
-Impulse generating and conducting region of a neuron
-Extends from the cell body at the structure called the axon hillock
Each neuron has ____ axon(s).
Each neuron has ONE axon.
Axon collaterals
Side branches from an axon
-May increase the contact point for an axon
End Branches (Terminal Branches or Telodendria)
Where the axon ends in branches
Function of an Axon
Generates and transmits action potentials
Axonal terminals hold ____.
Axonal terminals hold neurotransmitters.
Axonal Terminal
Secretory component of a neuron
Terminal branches of an axon end in knob-like structures called _____.
Terminal branches of an axon end in knob-like structures called axonal terminals (boutons or synaptic knobs).
Why is the axon incapable of protein synthesis?
Because the axon lacks nissil bodies and golgi.
_____ is possible in the axon but ____ is not.
Regeneration is possible in the axon but mitosis is not.
Regeneration of the axon is possible only in the ____ and not in the ____.
Regeneration of the axon is possible only in the PNS and not in the CNS.
What is the Integumentary System composed of?
1) The integument (skin)
2) Appendages of the skin
What is the largest organ of the body?
The skin (integument)
2 types of skin
1) Thin Skin
2) Thick Skin
Location of Thick Skin
-Palms of hands
-Soles of feet
Location of Thin Skin
Everywhere except in the palms of hands and soles of feet
2 Main layers of skin
1) Epidermis (superficial layer)
2) Dermis (deep layer)
Epidermis is composed of ____ (4 strata) and _____ (5 strata).
Epidermis is composed of Thin Skin (4 strata) and Thick Skin (5 strata).
Name the strata (sublayers) of the epidermis. [Deepest stratum to the most superficial stratum]
1) Stratum Basale [Deepest]
2) Stratum Spinosum
3) Stratum Granulosum
4) Stratum Lucidum ***(only in THICK skin)***
5) Stratum Corneum
Stratum Basale
-Deepest stratum of the epidermis abutting (next to) the dermis
-Composed of a single layer of epithelial cells
3 Types of cells in the Stratum Basale
1) Keratinocytes
2) Melanocytes
3) Merkel cells
Keratinocytes
Epithelial cells that produce a tough fibrous protein called keratin.
Stratum basale is also referred to as the ....?
Stratum germinatium
Keratinocytes undergo ____ to produce all the superficial strata with keratinocytes.
Keratinocytes undergo mitosis to produce all the superficial strata with keratinocytes.
Keratin
Tough fibrous protein produced by keratinocytes in the stratum basale
_____ in the stratum basale are highly mitotic, and hence the stratum basale is also referred to as the stratum germinatium.
Keratinocytes in the stratum basale are highly mitotic, and hence the stratum basale is also referred to as the stratum germinatium.
Melanocytes
-Cells that produce a brown-black pigment called melanin
Melanin
A brown-black pigment produced by melanocytes in the stratum basale
Function of Melanin
Acts as a chemical shield to protect the keratinocytes from the harmful effects of UV radiation in sunlight (UV radiation destroys DNA in the nucleus)
Merkel Cells
Half-moon shaped cells (hemispheres) present in the stratum basale
Function of Merkel Cells
Merkel cells associate with free nerve ending at the epidermal-dermal junction to form Merkel discs (function as touch receptors).
Stratum Spinosum
-Directly superficial to the stratum basale
-Composed of several layers of cells
-Cells closely packed and held together by desmosomes
-Tonofilaments abundant
-Appear spiky as they shrink
-Langerhan's cells present
Tonofilaments
Tension-resisting intermediate filaments that act to hold the stratum spinosum together
Langerhan's Cells
-Star-shaped epidermal dendritic cells present in the stratum spinosum
-Act as phagocytes to engulf and destroy pathogens
Stratum Granulosum
-Directly superficial to the stratum spinosum
-Composed of 3-5 layers of flattened cells
-Disintegrating nuclei and cytoplasmic organelles
2 Types of Granules in Stratum Granulosum
1) Lamellated Granules
2) Keratokyaline Granules
Lamellated Granules
Contain waterproofing glycolipids
Keratokyaline Granules
Contain keratin
Stratum Lucidum
-Only present in THICK skin
-Directly superficial to the stratum granulosum
-Composed of 2 layers of clear cells with no nuclear or cytoplasmic organelles (cells are dead)
Stratum Lucidum is ____ in thin skin.
Stratum Lucidum is ABSENT in thin skin.
Stratum Corneum
-Directly superficial to stratum granulosum in thin skin
-Directly superficial to stratum lucidum in thick skin
-Composed of 20-30 layers of flattened dead cells impregnated with keratin and glycolipids
Function of the Stratum Corneum
Protects the skin below it subjected to the most trauma (physical, chemical, biological, etc.)
What is dandruff?
The shedding of the stratum corneum
2 Sublayers (stratum) of Dermis
1) Papillary (superficial) layer
2) Reticular (deep) layer
Papillary Layer of the Dermis
-Directly inferior to the stratum basale of the epidermis
-Composed of a thin layer of areolar CT
-Dermal Papillae on surface
Dermal Papillae
Peglike projections present on the surface of the papillary layer of the dermis; supported by dermal ridges in thick skin
What is housed within the Papillary layer of the dermis?
a) Blood capillaries
b) Free nerve endings (act as pain receptors)
c) Meissner's corpuscles (act as touch receptors)
Dermal Ridges
-Raised, large dermal papillae present in thick skin
-Indent the overlying epidermis causing epidermal ridges
Epidermal Ridges
-Caused by dermal ridges indenting the overlying epidermis
-Located on the surface of the epidermis in thick skin (palms of hands and soles of feet)
-Patterns of epidermal ridges are unique to the individual
-Basis for fingerprinting
Patterns of _____ are genetically determined; the pattern is unique to the individual.
Patterns of epidermal ridges are genetically determined; the pattern is unique to the individual.
How does fingerprinting work in relation to the epidermal ridges?
-Sweat pores open along the epidermal ridges
-Patterned film is left on everything touched
-Pattern is unique to the individual (genetically determined)
Reticular Layer of the Dermis
-Deeper layer
-80% of the dermis total thickness
-Composed of dense, irregular CT
-Thick bundles of collagen fibers arranged in an irregular fashion
The _____ layer of the dermis is referred to as "hide" in animals.
The reticular layer of the dermis is referred to as "hide" in animals.
What is housed within the reticular layer of the dermis?
-Skin appendages
-Pacinian corpuscle
Cleavage Lines
Less dense areas (decreased #'s of collagen fibers) in the reticular layer of the dermis
Incisions made along ____ appear less gaping and heal faster.
Incisions made along cleavage lines appear less gaping and heal faster.
Pacinian Corpuscle
Acts as touch receptor for dep pressure within the reticular layer of the dermis
Straie
-Stretch marks
-Forms as a result of the dermis being torn
Burns
Damage to the skin by heat, electricity, chemical or physical trauma
3 Types of Burns (based on severity)
1) First Degree Burn
2) Second Degree Burn
3) Third Degree Burn
First Degree Burn
Damage to only the epidermis
(Example: sunburn)
Characteristics of First Degree Burn
Redness
Swelling
Pain
How long does First Degree Burn take to heal without medical intervention?
~3 days
Second Degree Burn
Damage to the epidermis and superior region of the dermis
Characteristics of Second Degree Burn
Redness
Swelling
Pain
Blisters
Blister
Fluid collected at teh epidermal-dermal junction
How long does Second Degree Burn take to heal?
-If blisters remain intact, second degree burn heals within 3 weeks without medical intervention.
-If blisters open, infection occurs and healing requires medical intervention.
Third Degree Burn
Damage to the entire skin (Damage to the epidermis and the entire dermis)
Characteristics of Third Degree Burn
Blackened
No pain
Areas immediately surrounding the burn site become reddish, swollen and painful
How long does Third Degree Burn take to heal?
-Healing requires medical intervention
-Involves debridement and grafting to prevent infection, water loss, and to encourage healing
Why is there no pain associated with third degree burn (at the burn site)?
Because nerve endings, which act as pain receptors, are destroyed
Types of Skin Cancers
1) Basal Cell Carcinoma
2) Squamous Cell Carcinoma
3) Melanoma
4) Adinoma
Basal Cell Carcinoma
-Cancer cells originate from the stratum basale
-Least malignant skin cancer
-Usually occurs in areas exposed to the sun
Squamous Cell Carcinoma
-Cancer cells originate from the stratum spinosum
-Can be malignant and metastasize if not removed
Melanoma
-Cancer cells are of the melanocytes
-Highly metastatic
-Resistant to chemotherapy
-Deadly if not removed
Adinoma
Cancer of the glandular tissue
Appendages of the skin are ALL derived from the ____ but reside in the ____.
Appendages of the skin are ALL derived from the epidermis but reside in the dermis.
Sweat Gland (Suderiforous Gland)
Simple coiled tubular exocrine gland
2 Major Types of Sweat Glands
1) Eccrine
2) Apocrine
Eccrine Sweat Glands
-Merocrine sweat glands
-Merocrine mode of secretion
-Produce sweat
Sweat
Hypotonic filtrate of blood
Composition of Sweat
-99% Water
-Antibodies
-Water soluble vitamins (B&C)
-Salt
-Metabolic wastes
-Dermicidin
Dermicidin
Anti-microbrial protein component of sweat
What is the pH of sweat?
Between 4-6 (acidic)
Explain the action of Sweat as an Acid Mantle.
Sweat is acidic which prevents the growth of microorganisms on the surface of the skin.
Explain Thermoregulation using Sweat
-Sweating cools the body down
-Body heat is used to evaporate sweat
Apocrine Sweat Glands
-Merocrine mode of secretion used
-Become active after puberty
-Influenced by hormones
-Secrete a viscous fluid rich in proteins & lipids after activation
Location of Apocrine Sweat Glands
-Axillary (armpits) region
-Pubic region
Apocrine sweat glands are also referred to as....?
Odoriferous Glands
How do Apocrine Sweat Glands contribute to body odor?
If the viscous fluid secreted by apocrine sweat glands accumulates in the armpit/pubic regions, microorganisms digest the proteins and lipids releasing sulfides.
2 Specialized Sweat Glands
1) Ceruminous Glands
2) Mammary Glands
Where are Ceruminous Glands located?
In the external auditory canal (ear)
What do Ceruminous Glands produce?
Cerumen
Cerumen
A waxy substance produced by ceruminous glands in the ear (aka ear wax)
Where are Mammary Glands located?
In the breast
What do Mammary Glands produce?
Milk during lactation to feed the young
3 Types of Skin Appendages
1) Sweat Glands
2) Sebaceous (Oil) Glands
3) Hairs (Pili)
Sebaceous Glands (Oil Glands)
-Simple, branched alveolar exocrine glands
-Holocrine mode of secretion
-Associated with hair follicles or open directly to surface
-Produce sebum
Sebum
-Product of sebaceous glands that consists of oil and cell debris
-Lubricates the hair and skin
Explain the formation of ACNE in relation to sebum.
Inflammation and infection of the sebaceous glands and ducts leads to acne.
Explain the formation of whiteheads in relation to sebum.
When the sebum production is increased under the influence of sex steroid hormones at puberty, the ducts become blocked with sebum... leading to whiteheads.
Explain the formation of blackheads in relation to sebum.
Oxidation and blackening of whiteheads... leads to blackheads.
General properties of Hair
-All mammals have hair
-Hairs provide protection
-Humans have sparse hair distribution
Hair on the scalp of humans serves what purpose?
Protects the skull from heat loss and trauma
Vibrissae
-Hair in the nasal cavity
-Filters coarse substances from inhaled air
Where are Nonciliated Pseudostratified Columnar Epithelium located?
In male's sperm-carrying ducts and ducts of large glands
2 Subclasses of Exocrine Glands
1) Unicellular
2) Multicellular
Unicellular Exocrine Gland
Single cells in epithelial tissue
Goblet Cell
-A type of unicellular exocrine gland
-Secrete mucin into body cavities
Mucin
A complex glycoprotein that dissolves in water when secreted by goblet cells; once dissolved it forms mucus.
Multicellular Exocrine Gland
Has epithelium-derived ducts
Simple glands
Multicellular exocrine gland with a straight duct structure
Compound glands
Multicellular exocrine gland with a branched duct structure
3 Categories of Multicellular Exocrine Glands (based on secretory units)
1) Tubular: tube-like
2) Alveolar (acinar): flask-shaped
3) Tubuloalveolar (tubuloacinar): combo of both shapes
Fibroblasts
Make Connective Tissue Proper
Chondroblasts
Make cartilage
Osteoblasts
Make bone
Hematopoetic stem cells
Make blood
All classes of Connective tissue have _____ around the cells.
All classes of Connective tissue have extracellular matrix around the cells.
Ground substance
-Interstitial fluid
-Cell adhesion proteins
-Proteoglycans
-GAGs
Proteoglycans
Made of protein cone + large negatively charged polysaccharide
Glycosamino glycans (GAGs)
The negative polysaccharides
Examples: chondroitin sulfate and hyaluronic acid
The more ____, the more viscous the ground substance is.
The more GAGs, the more viscous the ground substance is.
What are Collagen Fibers made of?
Collagen - a tough insoluble protein
4 Types of Covering and Lining Membranes
1) Cutaneous
2) Mucous
3) Serous
4) Synovial
In a cross section if hair appears flat... what type of hair is it?
Curly hair
In a cross section if hair appears oval... what type of hair is it?
Wavy hair
In a cross section if hair appears round... what type of hair is it?
Straight hair
2 Regions of Hair
1) Shaft
2) Root
Shaft
Region of hair above the skin
Root
Region of hair below the skin enclosed by the hair follicle
Hair Matrix
Cells in the hair matrix are mitotically active and they produce new hair
3 concentric rings of hair
1) Inner Medulla
2) Middle Cortex
3) Outer Cuticle
Function of the outer cuticle of hair
Protects the 2 layers within (inner medulla and middle cortex)
Nail
-A clear, scale-like modification of the epidermis
-Skin appendage
-Covers the dorsal surface of fingers and toes
Function(s) of the Nail
Grasping of small items
Scratching
3 Regions of the Nail
1) Free Edge - extends from digit
2) Body
3) Root - embedded in skin
Nail Matrix
A patch of dermal tissue located beneath the nail body; consists of mitotically active cells producing the nail.
Bones are classified based on ____.
Bones are classified based on shape.
Long Bones
-Longer than they are wide
-In appendicular skeleton with the exception of the tarsals
Short Bones
-Cube shaped
-Carpals, tarsals
Sesamoid Bones
Specialized type of short bones that are embedded in tendons
(Example: Patella of the knee)
Flat Bones
Flattened bones, usually thin
(Examples: sternum, ribs, cranial bones)
Irregular Bones
Shape of the bone does not fit into the other 3 categories
(Example: vertebrae)
4 Classes of Bones (based on shape)
1) Long Bones
2) Short Bones
3) Flat Bones
4) Irregular Bones
2 Regions of a Long Bone
1) Diaphysis
2) Epiphysis
Diaphysis
-Long axis or shaft of the bone
-Composed of a collar of dense (compact) bone tissue surrounding the medullary cavity
The Medullary Cavity contains ____ in children and ____ in adults.
The Medullary Cavity contains red bone marrow in children and yellow bone marrow in adults.
Red Bone Marrow is the site of _____.
Red Bone Marrow is the site of hematopoiesis (production of blood cells).
Epiphysis
Thin plates of compact bone surrounding spongy bone
The junctions between the epiphysis and the diaphysis are ____ and ____.
The junctions between the epiphysis and the diaphysis are the Epiphyseal Plates and Epiphyseal Lines.
Epiphyseal Lines
-Present at the diaphyseal-epiphyseal junctions in the long bones of adults
-Remnants of the epiphyseal plates after ossification
Epiphyseal Plates
Allow for longitudinal growth of long bones
Articular Cartilage
A thin cartilage composed of hyaline cartilage that covers the surfaces of the epiphysis
The surfaces of the epiphysis are covered by a thin cartilage called the ____.
The surfaces of the epiphysis are covered by a thin cartilage called the Articular Cartilage.
The diaphysis is surrounded by the ____.
The diaphysis is surrounded by the Periosteum.
Periosteum
A double-layered membrane that surrounds the diaphysis
2 Layers of Periosteum
1) Inner Osteogenic Layer
2) Outer Fibrous Layer
Fibrous Layer of the Periosteum is composed of....?
Dense irregular CT
Osteogenic Layer of the Periosteum is located where?
Abuts the surface of the diaphysis
2 Types of Cells contained within the Osteogenic Layer of the Periosteum
1) Osteoblasts
2) Osteoclasts
Osteoblasts
Bone forming cells
Osteoclasts
Bone resorbing cells; breakdown bone tissue
The internal surface of the medullary cavity and the trabeculae of the spongy bone in the epiphysis are covered by the ____.
The internal surface of the medullary cavity and the trabeculae of the spongy bone in the epiphysis are covered by the Endosteum.
Endosteum
Delicate CT membrane that contains osteoblasts and osteoclasts
Sharpey's (Perforating) Fibers
A tuft of collagen fibers that secures the periosteum to the surface of the diaphysis.
The periosteum is secured to the surface of the diaphysis by a tuft of collagen fibers called the _____.
The periosteum is secured to the surface of the diaphysis by a tuft of collagen fibers called the Perforating or Sharpey's Fibers.
Compact bone is composed of structural units called ___.
Compact bone is composed of structural units called Osteons (or Haversian systems).
Lamallae
Concentric tubes of bone tissue that composes each osteon
Compact bone is also known as...?
Lamellar Bone
Lacunae
Shallow concave cavities in the solid bone matrix
At the junction of adjacent lamellae, the osteoblasts mature into ____ which reside in the lacunae.
At the junction of the adjacent lamellae, the osteoblasts mature into osteocytes which reside in lacunae.
Haversian Canal
-In the core of the Osteon
-Contains blood vessels, lymphatic vessels and nerve fibers
Perforating Vessels
Blood vessels from the fibrous layer of the periosteum
Perforating vessels enter the compact bone though canals called ___ to connect with the blood vessels in the Haversian canals.
Perforating vessels enter the compact bone through canals called Perforating (Volkmann's) Canals to connect with the blood vessels in the Haversian canals.
Canaliculi
Small canals that connect the osteocytes to each other and connect osteocytes to blood vessels in the Haversian canal.
Common Characteristics of Flat, Short and Irregular Bones
-Osteons absent
-Composed of thin plates of periosteum covered compact bone outside and endosteum covered bone inside
-Medullary cavity absent
What is Spongy Bone composed of?
Trabeculae
How do trabeculae help the Spongy bone?
Trabeculae align at the point of stress placed on the bone to help the bone resist tension.
What function does the solid ground substance of bone tissue serve?
Provides the bone the ability to resist compression
Hydroxyapetities
-Calcium phosphate crystals
-15% of the mass of the extracellular matrix of Bone Tissue
-Contribute to hardness of ground substance
What function do collagen fibers serve in bone tissue?
-Provide tensile strength
-Arrangements provide bone tissue the ability to withstand twisting forces
How are collagen fibers arranged in bone tissue?
Collagen fibers in osteoid are arranged in opposite directions in adjacent lamellae.
What is the inorganic matrix of bone tissue composed of?
Hydroxyapetites
When does formation of the bony skeleton occur?
Prenatally
What is the Embryonic Skeleton composed of?
1) Fibrous Membrane
2) Hyaline Cartilage
When does ossification begin?
8 weeks after gestation
Fibrous Membrane
A thin membrane secreted directly by the mesenchyme
Mesenchyme
Embryonic CT
Gives rise to all types of cells
Intramembranous Ossification
Conversion of fibrous membrane into bone
Process of Intramembranous Ossification
a) Mesenchymal cells in fibrous membrane transform into osteoblasts
b) Osteoblasts secrete bone tissue
Membrane Bones
Bones formed via intramembranous ossification
(Examples: cranial bones and clavicle)
All membrane bones are ____ bones. But not all _____ bones are membrane bones.
All membrane bones are flat bones. But not all flat bones are membrane bones.
How are all bones (except the membrane bones) formed?
Endochondral Ossification
During development, mesenchymal cells differentiate into ___, which then secrete hyaline cartilage.
During development, mesenchymal cells differentiate into Chondroblasts, which then secrete cartilage.
Steps of Endochondral Ossification
1) Perichondrium surrounding hyaline cartilage is converted into periosteum
2) Osteoblasts secrete bone tissue
3) Chondroblasts mature into chondrocytes and eventually die, results in deterioration of the hyaline cartilage matrix
4) Matrix of bone tissue fills in and is mineralized
5) In long bones, osteoclasts resorb the center of newly formed bone tissue to create a medullary cavity. This cavity is invaded by red bone marrow.
6) Before or right after birth, expanded ends of hyaline cartilage (with the shaft already converted to bone tissue) become ossified. Creating the epiphysis in long bone.
7) After completion of process, hyaline cartilage still remains in 2 regions of long bone.
Where does hyaline cartilage remain in the long bone after completion of endochondral ossification?
a) Capping ends of the epiphysis as the articular cartilage
b) At the epiphyseal plates (at the end of the epiphyseal-diaphysis junction)
2 Types of Post Natal Bone Growth
1) Linear
2) Appositional
Where does linear bone growth occur?
At the epiphyseal plate in long bones
5 Zones in the Epiphyseal Plate (from the epiphyseal face to the diaphyseal face to the epiphyseal plate)
1) Resting Zone
2) Growth (Proliferation) Zone
3) Hypertrophic Zone
4) Calcification Zone
5) Ossification Zone
The Resting Zone is in contact with the ____.
The Resting Zone is in contact with the epiphysis.
Growth (Proliferation) Zone
-Chondroblasts are mitotically active
-Chondroblasts are secreting and adding hyaline cartilage
Hypertrophic Zone
Matured chondroblasts (chondrocytes) have hypertrophy (increased size and eventually die, causing deterioration of the hyaline cartilage matrix
Calcification Zone
Mineralization of the remnants of the hyaline cartilage matrix
Ossification Zone
Osteoblasts migrate into site and secrete new bone tissue
The amount of new hyaline cartilage formed in the growth zone is ____ to the amount of new bone added in the ossification zone.
The amount of new hyaline cartilage formed in the growth zone is EQUAL to the amount of new bone added in the ossification zone.
What allows lengthening of the medullary cavity?
Slight bone resorption in the center of the ossification zone
How is the diaphysis lengthened?
The epiphyseal plates shift during linear bone growth
Types of hormones controlling Linear Bone Growth
-Growth Hormone
-Sex Steroid Hormones
Where is Growth Hormone (GH) produced?
Pituitary gland in the brain
How does Growth Hormone (GH) affect linear bone growth?
Indirectly, via the production of Insulin-like Growth Factors (IGFs)
Describe the effect and process of Growth Hormone on linear bone growth.
-GH stimulates hepatocytes (liver cells) to synthesize IGFs
-IGFs bind to the chondroblasts in the growth zone
-Mitosis of the chondroblasts is stimulated
-Increased hyaline cartilage added on the epiphyseal face of the epiphyseal plate
-Hyaline cartilage ossified
How do Testosterone/Estrogens work in linear bone growth?
-Work together (synergize) with Growth Hormone to increase IGF production
-Results in increased lengthening of long bones
Growth spurt
Rapid growth phase after puberty when Testosterone/Estrogens work together with GH to increase IGF production resulting in increased lengthening of long bones
After 4-5 years from puberty, the testosterone/estrogens ____ GH-induced IGF production.
After 4-5 years from puberty, the testosterone/estrogens inhibit GH-induced IGF production.
Closure
-The ossification of the entire epiphyseal plates
-When linear bone growth ceases and height is determined
Appositional Bone Growth
-Results in increase in diameter/width of bones
-Occurs in all classes of bones
-Occurs throughout life
Sequence of events in Appositional Bone Growth
1) Osteoblasts in the osteogenic layer of the periosteum secrete new bone tissue onto the surface of the bone, increasing its width.
2) Osteoclasts in the endosteum slightly resorb old bone in the internal surface
***Bone formation on the external surface exceed bone resorption on the internal surface, resulting in increased width/diameter of the bone.
How does the process of Appositional Bone Growth prevent the bones from becoming bulky?
The osteoclasts in the endosteum will slightly resorb old bone in the internal surface
The 2 Opposite, Dynamic and Equal Processes that occur throughout life in bone remodeling
1) Bone deposit (formation)
2) Bone resorption
In bone remodeling the rate of bone deposit is ___ to the rate of bone resportion.
In bone remodeling the rate of bone deposit is EQUAl to the rate of bone resorption.
What are the purposes of bone remodeling?
a) Repair after bone fracture
b) Calcium homeostasis
What is the normal Calcium level in the blood?
9-11mg / 150cc blood
99% of Calcium is in the what form when stored in the bones?
Hydroxyapetites
What happens when calcium levels fall below 9mg/150cc of blood (hypocalcemia)?
Bone resorption occurs to release Calcium into the blood
What happens when calcium levels rise above 11mg/150cc of blood (hypercalcemia)?
Bone formation and mineralization occurs to move Calcium into the bones for storage
2 Factors that control bone remodeling
1) Gravitational (Mechanical) Factors
2) Hormonal Control
Wolff's Law
States that bone remodels and grows in response to the gravitational or mechanical stresses placed on that bone.
Forms of evidence in support of Wolff's Law
-Astronauts lose bone density in space (lack of gravitational pull on bones)
-Bed-ridden individuals without exercises will lose bone density (lack of gravitational pull)
-Paralyzed individual loses bone density (lack of mechanical stresses)
-Thick tarsals & phalanges of ballerinas (increased stress on these bones as they dance "en pointe")
-Weight lifters have thickening at the insertion sites of very active muscles (active muscles pull - mechanical stress - on the insertion sites)
-Braces on teeth (mechanical stress causes the teeth to reset in the alveolar sockets)