Tissue
Collection of specialized cells with discrete structural and functional properties
Organs
Tissues come together to form them so specific functions can be carried out
The four major types of human body tissue
Epithelial tissue, connective tissue, muscle tissue, neutral
Histology
Study of tissues
Epithelial tissue
Covers exposed surfaces, lines internal passageways, forms glands
Connective tissue
Fills internal spaces, provides internal support, transports material within the body, stores energy
Muscle tissue
Specializes in muscle contraction; includes skeletal muscle, cardiac muscle, and the smooth muscle of hollow organs
Neural tissue
Concentrates in the brain and spinal cord, carries electrical impulses from one part of the body to another
What does the epithelial tissue cover
The surface of the skin
What does the epithelial tissue line
Digestive, respiratory, reproductive, and urinary tracts
What does the epithelial tissue consist of?
Two components, which are the epithelia and glands
Epithelia
Layers of cells covering internal or external surfaces
Glands
Structures that produce fluid secretions
What are the characteristics of epithelial tissue/
Cellularity, polarity, attachment, avascularity, regeneration
What does the cellularity characteristic of epithelia refer to
Epithelia are made almost entirely of cells bound closely together by interconnections known as cell junctions
What does the polarity characteristic of epithelia refer to
The presence of structural and functional differences between the exposed and attached surfaces of the epithelia
What does the attachment characteristic of epithelia refer to
The base of an epithelium is bound to a thin, noncellular basement membrane which adheres to the basal surface and to the underlying tissues to establish the cell's border and resist stretching
What does the avascularity characteristic of epithelia refer to
They lack blood vessels
How do epithelial cells get nutrients?
By diffusion or absorption across either the exposed or the attached epithelial surface
What does the regeneration characteristic of epithelia refer to?
Epithelial cells that are damaged or lost at the exposed surface are continuously replaced through stem cell divisions in the epithelium?
What are the 2 surfaces of epithelial tissue
Apical surface, basolateral surface
Apical surface of epithelia
Where the cells are exposed to the internal or external environment
Basolateral surface of epithelia
Where the cells attach to an underlying structure and to the sides for contact with other cells
What does the apical surface of some epithelium contain?
Cilia or microvilli
Cilia
Creates sweeping motion, helps move substances over its surface
Microvilli
Aids in the process of absorption by increasing surface area
What are the four main functions of epithelial tissue
Physical protection, permeability, sensation, specialized sensations
What does the physical protection function of the epithelial tissue refer to?
Acts as a barrier. protects exposed and internal surfaces from abrasion, dehydration, and destruction by chemical or biological agents
What does the permeability function of the epithelial tissue refer to?
Any substances that enters or leaves your body must cross an epithelium. some epithelia are relatively impermeable. others are easily crossed by compounds as large as proteins.
What does the sensation function of the epithelial tissue refer to?
Epithelia are extremely sensitive to stimulation, because they have a large sensory nerve supply
What does the specialized sensations of the epithelial tissue refer to?
Epithelial cells that produce secretions are called gland cells
What are epithelial cell specialized for?
The movement of fluids over the surface, the movement of fluids through the epithelium, the production of secretions for physical protection or chemical messaging
What does the epithelium have to do to be effective as a barrier?
Form a complete covering or lining
What are the three factors that help epithelium maintain its integrity?
Process of regeneration and repair, attachment to the basement membrane, has cellular connections
Why do epithelial cells firmly attach to one another?
To allow for cellular communication and structural support
What are CAMs?
Cell adhesion molecules
Cell adhesion molecules
Transmembrane proteins that help bind cells to each other and to extracellular materials and the surrounding environment
Hyaluronan
Binds membranes of adjacent cells
What type of cell is hyaluronan?
Glycosaminoglycan
What are the three common types of epithelial intercellular connections?
Gap junctions, tight junctions, desmosomes
Gap junctions
Binds cytoplasm of one cell to cytoplasm of another cell
What are gap junctions formed by?
Interlocking channel proteins called connexon
What are connexon made up of?
6 connexin proteins
How do connexon form gap junctions?
By forming a narrow passageway that allow movement of ions and small molecules to pass
What do gap junctions aid in?
Rapid communication, coordination action between cells
What is another name for tight junctions?
Occluding junctions
What are tight junctions formed by?
The fusion of two plasma membranes
What is the function of tight junctions?
Trying to prohibit substances from passing through, prevents movement between cells
How do tight junctions function?
Interlocking proteins tightly bind the membranes, followed by an adhesion belt that lies deep to encircle the cells
What are desmosomes considered as?
Durable interconnections
What do desmosomes do?
Help cells resist stretching, twisting, and bending
What do desmosomes contain?
CAMs and proteoglycan links
What are the two types of desmosomes?
Spot desmosomes, hemidesmosomes
What do spot desmosomes connect to?
Intermediate filaments
What do spot desmosomes do/
Attach one epithelial cell to another, stabilize shape of cell
What do hemidesmosomes do?
Attach the cell to the basement membrane, anchor the cell to underlying tissues, stabilize cell's position
What are the two components of the basement membrane?
Clear layer, dense layer
What is another name for the clear layer of the basement membrane?
Basal lamina
What is the basal lamina?
A thin layer secreted by epithelial tissue, sits directly underneath base of epithelial tissue, produced by epithelial cells
What does the basal lamina contain?
Glycoproteins, network filaments
What does the basal lamina restrict/
The movement of proteins and large molecules
What is another name for the dense layer of the basement membrane?
Reticular lamina
Where is the reticular lamina relative to the basal lamina?
Deeper; covers larger portion
What is the reticular lamina?
Thick layer produced by connective tissue
What does the reticular lamina contain?
Coarse protein fibers
What does the reticular lamina do?
Provides strength to the basement membrane
How do cells maintain their structure and constant reproduction?
By continual division of stem cells
What is another name for stem cells?
Germinativum cells
Where are germinativum cells located?
Near the basement membrane
Why do stem cells reside near the basement membrane?
Because it's more of a protected region, instead of being exposed to the surface.
What are stem cells of epithelia sometimes referred to as?
Basal cells
What are the two things epithelial cells can be categorized by?
Shape, number of layers
How can epithelial cells be categorized by shape?
Squamous, cuboidal, columnar
How do squamous cells appear?
Flat and thin
How do cuboidal cells appear?
With a box-like shape
How do columnar cells appear?
Like slender rectangles
What is a simple epithelium?
Epithelial cell that contains one layer
What does simple epithelium line?
Internal passageways and compartments
Where is simple epithelium found?
Regions where secretion or absorption occurs
What does stratified epithelium contain?
Multiple layers (layers of cells stacked one upon the other)
Where are stratified epithelia found?
Areas exposed to stress, like skin
What is a transitional epithelium?
A unique type of stratified epithelium where cells change shape
Where is transitional epithelia?
In the urinary system, particularly in the bladder
When do the apperances of transitional epithelia change/
With stretching
What does transitional epithelia endure?
Stretching and recoiling without damage
Give an example of transitional epithelia in the urinary bladder.
When the urinary bladder is empty (relaxed), cuboidal cells are present. when the urinary bladder is full (contracted), squamous cells are present.
Transitional epithelium is found in
urinary bladder; renal pelvis; ureters
Simple squamous epithelium is found in
mesothelia lining pleural, pericardial and peritoneal cavities, endothelia lining heart and blood vessels, portions of kidney tubules (thin sections of nephron loops), inner lining of cornea, alveoli of lungs
Stratified squamous epithelium is found in
Surface of skin; lining of mouth, throat, esophagus, rectum, and vagina
Functions of stratified squamous epithelium
Provides physical protection against abrasion, pathogens, and chemical attack
Function of simple squamous epithelium
Reduces friction; controls vessel permeability; performs absorption and secretion
Simple cuboidal epithelium is found in
Glands; ducts; portions of kidney tubules; thyroid gland
Functions of simple cuboidal epithelium
Limited protection, secretion, absorption
Stratified cuboidal epithelium is found in
Lining of some ducts
Functions of stratified cuboidal epithelium
Protection, secretion, absorption
Simple columnar epithelium is found in
lining of stomach, intestine, gallbladder, uterine tubes, collecting ducts of kidneys
Function of simple columnar epithelium
Protection, secretion, absorption
Pseudostratified ciliated columnar epithelium is located in
lining of nasal cavity, trachea, and bronchi; portions of male reproductive tract
Functions of pseudostratified ciliated columnar epithelium
Protection, secretion, move mucus wit cilia
Stratified columnar epithelium is found in
Small areas of the pharynx, epiglottis, anus, mammary glands, salivary glands, gland ducts, urethra
Functions of stratified columnar epithelium
Protection
What does the microvilli do
Increase surface area to allow for better absorption
Glandular epithelia
Epithelial cells that produce secretions
What are the two types of glands?
Endocrine, exocrine
Endocrine glands
Release hormones directly into the bloodstream
Exocrine glands
Release secretions into some type of duct and then from the duct it is transferred onto the surface
What are the three types of glandular secretion
Merocrine, apocrine, holocrine
Merocrine secretion
Release products in vesicles via exocytosis
Exocytosis
release of substances out a cell by the fusion of a vesicle with the membrane.
Apocrine secretion
Release products by shedding
Holocrine secretion
Release products by the continual regeneration of the cell to free its contents; the cell is destroyed and is replaced by stem cells to continue secreting
What is the most common method of secretion?
Merocrine secretion
Serous glands
Secrete a watery solution that contains enzymes
Mucous glands
Secrete mucins that hydrate to form mucus
Mixed endocrine glands
Contain more than one type of gland cell. these glands may produce two different exocrine secretions, one serous and the other mucous.
What are the different types of exocrine glands?
Serous glands, mucinous glands, mixed glands
What can exocrine glands be classified by?
Types of secretions they produce, structure
How can the duct of exocrine glands be classified?
Non-branching, branching
How do non-branching exocrine glands' ducts look?
They are single and undivided
How do the branching exocrine glands' ducts look?
Divides one or more times
How can the secretory gland portion of exocrine glands be classified?
Tubular, alveolar
What do tubular secretory exocrine glands form?
Tubes
What do alveolar secretory exocrine glands form?
Blind pockets (sacs)
What is an example of a simple tubular exocrine gland?
Intestinal glands
What is an example of a simple coiled tubular exocrine gland?
Merocrine sweat glands
What is an example of a simple branched tubular exocrine gland?
Gastric glands
What is an example of a simple alveolar exocrine gland?
Not found in adults; a stage in development of simple branched glands
What is an example of a simple branched alveolar exocrine gland?
Sebaceous glands
What is an example of a compound tubular exocrine gland?
Mucous glands
What is an example of a compound alveolar exocrine gland?
Mammary glands
What is an example of a compound tubular-alveolar exocrine gland?
Salivary glands
When is a gland considered simple?
If it has a single duct that does not divide on its way to the gland cells
When is a gland considered compound?
If the duct divides one or more times on its way to the gland cells
When is a gland considered to be branched?
If several secretory areas share a duct
Connective tissues
Connects the epithelium to the rest of the body
What are the three main components of connective tissues?
Specialized cells, extracellular fibers, fluid or gel-like components known as ground substance
Matrix
The extracellular fibers and the ground substance of a connective tissue when considered together
Functions of connective tissues
provides strength and stability; maintains relative positions of organs because it connects different tissues together; transports fluids and dissolved materials; stores energy in the form of triglycerides; defends against invading microorganisms
what are the categories that connective tissue can be classified into?
Connective tissue proper, fluid connective tissue, supporting connective tissue
Connective tissue proper
Loose connective tissue, dense connective tissue
Fluid connective tissue
Blood, Lymph
Supporting connective tissue
Bone, cartilage
Loose connective tissue
Considered the "packing material" of the body
What are the three types of loose connective tissue in the body?
Areolar, adipose, reticular
Areolar tissue
The least specialized loose connective tissue
What type of ground substance does areolar tissue have?
Viscous ground substance that provides volume and shock absorption
What does areolar tissue accomplish?
Separates skin from deep structures
What is adipose tissue composed of
Adipocytes
What are the two subtypes of adipose tissue
brown adipose tissue, white adipose tissue
What does brown adipose tissue do?
Speeds up fat breakdown and energy release
What does white adipose tissue do?
Stores fat, absorbs shock, insulates
Which type of adipose tissue predominates during development?
Brown fat
Where is the reticular tissue found?
Spleen, liver, lymph nodes, bone marrow
What does the reticular tissue do?
Provides supporting framework
Dense connective tissue
Connective tissue proper that is tightly packed with collagen or elastic fibers which help provide strength and flexibility
what are the two types of dense connective tissue
Dense regular tissue, dense irregular tissue
What are dense connective tissues often called?
Collagenous tissues
Why are dense connective tissues sometimes called collagenous tissues?
Because collagen fibers are the dominant type of fiber in them.
Dense regular connective tissue
Has tightly packed collagen fibers
Examples of dense regular connective tissue
Tendons, ligaments
Tendons
Attach muscle to bone
Ligaments
Attach bone to bone
Dense irregular connective tissue
Forms an interwoven meshwork of collagen fibers with no consistent pattern; has a thick, fibrous capsule; contains variable amounts of elastic fibers
What do fluid connective tissues contain?
A fluid matrix with dissolved proteins
What are the specific cell types that fluid connective tissues carry?
Red blood cells, white blood cells, platelets
What are the types of extracellular fluid in fluid connective tissues?
Plasma, interstitial fluid, lymph
Cartilage
A firm gel matrix
What does the cartilage do?
Provides shock absorption and protection
Bone
Has a calcified matrix
What does the bones do?
Provides weight support
What does the cartilage matrix consist of?
Proteoglycans, ground substance proteins, cartilage cells
What is another name for cartilage cells?
Chondrocytes
The chemical that inhibits vessel growth produced by chondrocytes
angiogenesis factor
Explain cartilage structure
Lacks blood vessels; is set apart from surrounding tissues by a fibrous perichondrium
What are the two layers of the perichondrium
An inner cellular region, an outer fibrous layer
What is the inner cellular region of the perichondrium for?
Growth
What is the outer fibrous layer of the perichondrium for?
Strength
What is the function of the perichordium?
Contains blood vessels that supply oxygen and nutrients to chondrocytes
What are the three types of cartilage found in the body?
Hyaline cartilage, elastic cartilage, fibrocartilage
What is the most common type of cartilage?
Hyaline cartilage
What is a characteristic of hyaline cartilage?
Tough yet flexible
What is hyaline cartilage packed with?
Collagen fibers
What does the hyaline cartilage do?
Reduces friction between bones
Where is the hyaline cartilage found?
Ribs, sternum, synovial joints
What does elastic cartilage contain/
Numerous elastic fibers
What is the characteristic of elastic cartilage?
Highly resilient, flexible
Where is elastic cartilage found?
External ear, epiglottis
What is the characteristic of fibrocartilage?
Extremely tough, durable
What is the function of fibrocartilage?
Preventa bone to bone contact; cushions knee joints
Where is fibrocartilage found?
Pubic bones, intervertebral discs
What are the two mechanisms by which cartilage grow?
Interstitial growth, appositional growth
Interstitial growth
Cartilage enlarges from within; chondrocytes divide and daughter cells secrete new matrix
Appositional
New cartilage layers are added to the surface; inner cells of the perichondrium divide becoming chondroblasts that secrete new matrix
What is osseous tissue?
bone
What does bone contain
Calcified calcium salts
What is bone made up of
Bone cells
What are the characteristics of one
Strong, highly resistant
What are bone cells calld?
Osteocytes
Where are osteocytes located?
Lacunae
How are osteocytes arranged?
Around central canals
What are the channels through the matrix of osteocytes called?
Canaliculi
What do canaliculi do?
Provide access to blood supply
Periosteum
Covers the surface of bones
What does the periosteum consist of?
A cellular and fibrous layer
What is the muscle tissue specialized for?
Contraction
What does muscle tissue produce?
All movement
What are the three types of muscle tissue?
Skeletal muscle, cardiac muscle, smoot muscle
What is the skeletal muscle for?
Gross body movement
What is the cardiac muscle for?
Blood circulation
What is the smooth muscle for?
Elasticity, contractility, support
Skeletal muscle cells are usually
Long, thin
How many nuclei do skeletal muscle cells possess?
Several hundred nuclei
How do skeletal muscle cells appear?
Striated
Do skeletal muscle cells undergo division?
No
Where do new fibers arise from in skeletal muscle cells?
Myosatellite cells
What are cardiac muscle cells known as?
Cardiocytes
How many nuclei do cardiac muscle cells possess?
A single nuclei
How are cardiac muscle cells connected to one anoteher?
By intercalated discs
What are cardiac muscle cells regulated by?
Pacemaker cells
Where are smooth muscle cells found?
Blood vessel walls, hollow organs
How do smooth muscle cells look?
Small, spindle-shaped
Where can neural tissue be found?
Brain, spinal cord
What is neural tissue specialized for?
Conducting electrical impulses
What does the neural tissue do?
Processes information to produce a response
What are the two types of basic cells found in neural tissue?
Neurons, neuroglia
What are neurons?
Nerve cells
What are neuroglia?
Supporting cells
What do neurons do?
Conduct electrical impulses throughout the body
What do neuroglia do?
Aid in repair and nutrient supply
What are the 3 cell parts of a typical neuron?
Cell body, multiple dendrites, axon
What does the cell body of a neuron contain?
Nucleus, nucleolus
What do the dendrites of neurons consist of?
Branches extending from the cell body that receives incoming signals
What does the axon of neurons consist of?
Long cell body extension that sends outgoing signals to their destination
What is the first response of the body to an injury?
Inflammation
What is inflammation characterized by?
Pain, redness, warmth, swelling
Inflammation
A process that isolates the injured area while damaged cells, tissue components and any dangerous microorganisms, which could cause infection, are cleaned up
What happens during the inflammatory response?
Injured cells release chemicals signals into the surrounding tissues
What do damaged cells release into the body during inflammation?
Proteins, potassium
What gets stimulated during inflammation?
Mast cells
What do mast cells release when stimulated during inflammation?
Histamine, heparin, prostaglandins
What does the chemical signals released by cells during inflammation lead to?
Vessel dilation
What does vessel dilation accomplish?
Increases blood circulation to the area, brings in more nutrients and oxygen, removes waste products, attributes to the redness and warmth associated with inflammation
What leads to swelling and pain during inflammation?
The diffusion of mast cells
What eventually happens to the injured cells?
They break down
What does the break down of injured cells release?
Enzymes that destroy the cell and attack surrounding tissues
What is tissue destruction known as?
Necrosis
When does necrosis occur?
Several hours after the injury
What is pus?
Collection of debris, fluid, dead and dying cells, and necrotic tissue components
Abscess
Accumulation of pus in an enclosed tissue space
What happens when pus becomes trapped?
Creates an abscess
Which cells clean up pus?
Macrophages
What happens once the injury or infection has been cleaned up by macrophages?
The process of healing begins
What happens during tissue regeneration?
Fibrocytes move into the necrotic region, new cells are introduced to the area, collagen fibers are laid down, the fibers bind together to form scar tissue
Which types of tissues are capable of regenerating after injury?
Epithelial tissue, connective tissue, smooth muscle
Which types of tissues are not capable of regenerating after injury?
Skeletal tissue, cardiac tissue, neural tissue
How does tissue structure change with aging?
The speed and effectiveness of tissue repair decreases which is likely related to the hormonal changes that occur
What are some of the effects of aging on the body?
Thinning of epithelial and connective tissues, increased bruising and bone fragility, increased joint pain and broken bones, higher likelihood of cardiovascular disease, mental deterioration
Integument
The body's largest organ system
How much of the total body weight does the integument occupy
16%
Approximately how much area does the integument cover in the body?
1.5 to 2 m2
What are the two major components of the integument?
Cutaneous membrane, accessory structures
What is the cutaneous membrane subdivided into?
An outer epidermis, an inner dermis
What type of tissue is the epidermis?
stratified squamous epithelium
What type of tissue is the dermis?
connective tissue
What is the layer that is deep to the dermis?
Hypodermis
What is another name for the hypodermis?
Subcutaneous layer
What are the accessory structures of the skin
Hair, hair follicles, exocrine glands, nails
Where do the accessory structures of the skin originate?
Dermis, but they extend into the epidermis and protrude to the skin surface
What are the major functions of the skin?
Protection of underlying tissues and organs against impact, abrasion, fluid loss, and chemical attack; production of melanin, which protects underlying tissue from ultraviolet radiation; maintenance of normal body temperature through either insulation or
What are some of the side functions of the skin?
Production of keratin, which protects against abrasion and repels water; synthesis of vitamin D3, a steroid that is converted to calcitriol, a hormone important to normal calcium ion metabolism; storage of lipids in adipocytes in the dermis and in adipose
What is the epidermis consist of
Keratinized stratified squamous epithelium, which provides physical protection against microorganisms
Keratinocytes
Cells that dominate the epidermis
What do keratinocytes contain large amounts of?
Keratin
What are the five layers of the epidermis, from superficial to deep?
Stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale
Where do basal cells live?
Stratum basale
Stratum corneum
Covers the exposed surface of the skin; has 15 to 30 layers of keratinized cells; is water resistant; contains cells that are shed and replaced nearly every two weeks
Stratum lucidum
Layer located deep to the stratum corneum; covers the stratum granulosum; can only be found in thick skin
Stratum granulosum
Located superficial to the stratum spinosum; contains cells that have stopped dividing; consists of layers derived from the spinosum; its cells produce keratin, a tough fibrous protein
Keratinization
The formation of superficial, protective layer of keratin; occurs on mostly all exposed skin surfaces
Stratum basale
The deepest layer of the epidermis; attaches to the basement membrane; forms a tight bond between the epidermis and dermis; forms epidermal ridges; contains many basal cells that replace shed superficial cells
Besides basal cells, what are other specialized cells of the stratum basale?
Merkel cells, melanocytes
What is another name for Merkel cells?
Touch receptor cells
What are Merkel cells?
Tactile cells found in hairless areas; respond to touch by triggering the nervous system
Melanocytes
Cells scattered throughout the stratum basale; pigment-producing cells
Epidermal growth factor
A powerful peptide growth factor produced by glands (salivary and duodenum)
What are the functions of the epidermal growth factor?
Promoting the divisions of basal cells in the stratum basale and stratum spinosum; accelerating keratin production; stimulating epidermal repair; stimulating glandular secretion
What are the two pigments that influences skin color?
Melanin, carotene
What is melanin produced by?
Melanocytes
What is melanin stored in?
Intracellular vesicles, melanosomes
Where does carotene accumulate?
Epidermal cells, fatty tissue
What can carotene be converted to?
Vitamin A
Explain melanin's role in dermal circulation
Red oxygenated blood is the contributor; as blood vessels dilate, the skin reddens; as blood vessels constrict, the skin pales
Cyanosis
A bluish tint to the skin that may result from severe decreases in blood flow or oxygenation
In addition to melanin and carotene, what is another factor that can impact skin color?
Illness
Jaundice
Yellow skin color due to bile buildup
Vitiligo
Melanocyte loss (they become destroyed) causing loss of color
Addison's disease
Pituitary tissue causing skin darkening
Ultraviolet radiation
Produces vitamin D which is good only in small amounts; causes DNA damage and sunburn which can lead to wrinkles and cancer risk
What do the melanin produced by melanocytes provide protection against?
Sun damage
What does skin color result from?
Melanin production, not the number of melanocytes present
What is the active form of Vitamin D?
Calcitriol
What is vitamin D produced by?
Epidermal cells after sun exposure
Which organs convert vitamin D to calcitriol?
Liver, kidney
What could insufficient levels of calcium cause?
Increased risk of abnormal bone development, such as Rickets
Where is the dermis located?
Between the epidermis and subcutaneous layer
What does the dermis do?
Anchors the accessory structures
What are the two major components of the dermis?
Inner reticular layer, outer papillary layer
What type of tissue is the inner reticular layer made of?
Dense irregular tissue
What does the inner reticular layer consist of?
Large capillaries, lymphatics, nerves
What type of tissue is the outer papillary layer?
Areolar tissue
What does the outer papillary layer contain?
Dermal papillae projections
What is dermal strength and elasticity provided by?
Collagen, elastic fibers
Elastic fibers
Can stretch and recoil to their original length; provide flexibility
Collagen fibers
Very strong and resist stretching; limit flexibility to prevent tissue damage
Skin damage
May occur due to destructive effects of UV radiation; may occur from aging and hormones; leads to a permanent decrease in skin elasticity
How does skin innervation occur?
By numerous sensory neurons
What does the epidermis contain?
Sensory neurons to detect touch, pain and temperature
What does the dermis contain?
Sensory neurons to detect touch, pain and temperature as well as special receptors sensitive to light touch
What are the two types of special receptors sensitive to light touch in the dermis?
Meissner corpuscles, pacinian corpuscles
Meissner corpuscles
Helps to detect touch
Pacinian corpuscles
Helps to detect pressure and vibration