tissues

human anatomy and physiology lecture 3

four primary tissue types

• epithelial tissue

• muscle tissue

• connective tissue

• nervous tissue

function of muscle tissue

contraction

arrangement of cells in muscle tissue

arranged in sheets, so each cell is oriented in the same way

three types of muscle tissue

• skeletal muscle

• cardiac muscle

• smooth muscle

skeletal muscle

muscle attached to bones

result of contraction of skeletal muscle

contraction results in movement of bones

is skeletal muscle under voluntary or involuntary control?

voluntary and involuntary

endurance of skeletal muscle

low endurance

cardiac muscle

constitutes the heart

result of contraction of cardiac muscle

pumps blood

is cardiac muscle under voluntary or involuntary control?

involuntary

endurance of cardiac muscle

high endurance

smooth muscle

constitutes the walls of tracts and blood vessels

is smooth muscle under voluntary or involuntary control?

involuntary

endurance of smooth muscle

medium endurance

neuromuscular junctions

where axon terminals interact with muscle fibers

muscle fibers

cells in skeletal muscle

intercalated discs

connections between cardiomyocytes for anchoring and communication, containing desmosomes and gap junctions

cardiomyocytes

cells in cardiac muscle

pacemaker cells

cells in heart to establish heart rate

role of desmosomes

hold two cells together

gap junction

pore that allows communication between two cells

peristalsis

wave of smooth muscle contraction to move bolus of food along gastrointestinal tract

inner circular muscles

constrict and dilate the diameter of the gastrointestinal tract

outer longitudinal muscles

lengthen and shorten the gastrointestinal tract

characteristics of skeletal muscle tissue

• perpendicular striations

• nuclei pushed to the edges of the cells

• large size

characteristics of cardiac muscle tissue

• striations

• central nuclei

• branching

• intercalated discs connecting adjacent cells

characteristics of smooth muscle tissue

• spindle shape

• lack of striations

• single nucleus

• small size

identify the type of muscle tissue

skeletal muscle

identify the type of muscle tissue

cardiac muscle

identify the type of muscle tissue

smooth muscle

four major functions of epithelial tissue

• protect against abrasion and dehydration

• often contain receptors that transmit sensation to the nervous system

• controls the entry and exit of substances into and out of the body

• epithelial cells actively secrete compounds into the surface of the epithelium

endocrine glands

secrete hormones into the bloodstream

exocrine glands

release substances onto the epithelium (out of the body)

epithelium

lines the inner surface of tracts

tract

tubular structure that is open to the outside environment

endothelium

lines the inner surface of blood vessels

hemidesmosomes

type of desmosomes connecting the deepest layer of epithelial cells to the basement membrane

avascular

no blood vessels are present

shape of squamous cells

short and flat

shape of cuboidal cells

similar length and width

shape of columnar cells

cells are taller than they are wide

simple cell layers

single layer of cells

stratified cell layers

more than one layer of cells

pseudostratified cell layers

single layer of cells of different heights

structure and functions of simple squamous epithelium

diffusion and filtration, reducing friction

structure and functions of simple cuboidal epithelium

secretion and absorption (glands), may have microvilli

structure and functions of simple columnar epithelium

secretion and absorption (along the gastrointestinal tract), may have microvilli or cilia

microvilli

brush-like border of a cell to increase surface area

structure and function of pseudostratified columnar epithelium

secreting and moving fluids (like mucus), limited capacity for protection against abrasion, infection, and chemicals, so cells must be regenerated more often, have cilia

ciliated simple columnar cells

moves the mucus spread on the upper airway upwards to the pharynx to be disposed of (swallowed or expectorated)

simple columnar goblet cells

secrete mucus in which dust particles and microorganisms present in the lumen of the respiratory tract get caught

function of stratified squamous epithelium

physical protection from abrasion, infection, and chemical attack, can be keratinized for extra protection

types of exocrine glands

unicellular and multicellular

unicellular exocrine glands

consist of a single cell

multicellular exocrine glands

have a secretory portion that secretes and a duct portion that transports

four types of connective tissue

• bones and cartilage

• tendons and ligaments

• blood

• fat

functions of bones and cartilage

support softer tissues and provide a solid framework

function of ligaments

bind two bones together

function of tendons

bind muscles to bones

functions of blood

carries and distributes many substances including hormones and nutrients

function of red blood cells

carry gases

function of white blood cells

defend against microorganisms

three types of protein fibers for the extracellular matrix

• collagen fibers

• elastin

• reticular fibers

collagen fibers

most common fibers in the extracellular matrix, are strong and flexible

elastin

provides elasticity

reticular fibers

thinner, less common than collagen, branch and interweave to create an organ’s shape

ground substance of the extracellular matrix

largely composed of proteoglycans, occurs in various states of fluidity, can slow the movement of pathogens

three categories of connective tissue

• supporting connective tissue

• connective tissue proper

• fluid connective tissue

supporting connective tissue

least fluid, includes bones and cartilage

connective tissue proper

loose and dense subtypes based on protein:cell ratio, regular and irregular subtypes based on arrangement of protein, most abundant

fluid connective tissue

most fluid, includes blood and lymph

features and functions of supporting connective tissue

provide support, leverage, and protection to underlying tissues and organs

features and functions of connective tissue proper

highly vascularized, provide support, cushioning, and protection, can be a storage reserve for energy, contain sensory nerves for pain, pressure, and temperature

features and functions of fluid connective tissue

involved in material transport, capable of mounting an immune reaction to defend against microbes

vascularization

presence of blood vessels

innervation

presence of nerves

connective tissue with high vascularization and innervation

• loose connective tissue

• dense irregular connective tissue

• bone

• fat

connective tissue with low vascularization and innervation

• tendons and ligaments

• cartilage

three types of cartilage

• hyaline

• elastic

• fibrocartilage

bone ground substance

mineralized with calcium phosphate and with protein fibers, helps resist compression and tension

cartilage cell type

chondrocytes

bone cell types

osteocytes, osteoblasts, osteoclasts

osteocytes

maintain bone

osteoblasts

produce new bone

osteoclasts

resorb bone

chondro-

cartilage

osteo-

bone

blood cell types

red blood cells, white blood cells, platelets

fibrinogen

primary protein fiber in blood

ground substance of blood

includes the main blood proteins, albumins and globulins

plasma

contains and transports hormones, antibodies, ions, plasma proteins, and urea

platelets

prevent blood loss at injury sites by adhering to the site of injury to temporarily plug the hole

leucocytes

immunosurveillance, inflammation and defense, prevention of infection from microorganisms, production of anitbodies

white blood cells

leucocytes

erythrocytes

delivers oxygen and transports a portion of metabolic wastes

red blood cells

erythrocytes

loose connective tissue proper

more cells in its tissues compared to dense connective tissue proper

dense connective tissue proper

less cells in its tissues compared to loose connective tissue proper

irregular dense connective tissue proper

protein fibers are organized randomly to support mechanical stress from many directions