Tissue Structure and Composition

Tissue types, bone, and muscle

Epithelium

Thin layer of tissue that essentially covers all free surfaces of the body

Principle Function: Epithelium

act as a barrier between tissues and external environment or internal body cavities

Sensory communication

Endothelium

_____ Covering the innermost

surfaces of capillaries

Controls nutrient flow into

underlying tissues, such as: Oxygen, hormones, proteins

Epithelial Tissues: Secretory Cells

• Contain extensive Endoplasmic reticulum

• Composition of cell products vary depending on substance needed at the cell surface

• Responsible for packing and transporting products to cell surface for release

Epithelial Tissues: Secretory Cells Example

Enzymes released from digestive tract

Epithelial Tissues: Secretory Cells Example

Goblet cells secrete Mucus,

muscus secretion respiratory tract or reproductive tract

Simple Epithelial tissue

single layer of cells

• Located where maximal secretion or absorption is necessary

• Delicate structure

Simple Epithelial tissue

Stratified Epithelual tissue

two or more cell layers

• Found where there is friction with outer environment

  • Chemical and mechanical perturbations

• Protect underlying tissues

Types of Epithelium Cells: Squamous

Types of Epithelium Cells: Cuboidal

Types of Epithelium Cells: Colummnar

Pseudostratified

cells that are there but not reaching the next membrane

Google Def: type of epithelial tissue that appears to be stratified (arranged in layers) but actually consists of a single layer of cells.

Translational Epithelium

Stratified Cuboidal epithelium but changes dramatically with distention of the underlying tissues

Located in: Bladder and parts of urinary tract

Nervous Tissue 

• Central nervous system: brain & spinal cord, non-voluntary

• Peripheral nervous system: sensory and motor neurons

  • Sensory-direct stimuli

  • Motor delivers a response message

Neurons

specialized cells that transmit signals throughout the body

Axon

projection of the cell to allows the transmission of a signal deep within a tissue

Cell body

contains the nucleus

Dendrites

where synaptic junctions are formed to perceive signals from other cells

Schwann Cell

form myelin sheath creating Nodes of Ranvier

• Rapid action potential firing

Components of Connective Tissue

• Fibers

• Ground Substance

• Cells

Connective Tissue: Extracellular Matrix

• Ground substance

• Chondritin

Ground substance

fluid-like structure of the Extracellular Matrix consisting of soluble proteoglycans

• Chondroitin sulfates

• Hyaluronic acid

proteoglycans

proteins linked to carbohydrates

Connective Tissue Fibers

• Collagen Fibers

• Reticular Fibers

• Elastin

Collagen Fiber

• Most abundant protein in animals (20-30%)

• Support

• Crosslinking

• Type 1-most abundant connective tissue in the body (80% of total _____)

  • Skin and Muscle

Procollagen

Collagen Precursor that is secreted from the fibroblast

Reticular Fibers

• Small and Delicate

• High proportion of ground substance

• Loose connective tissue

• Surround's organs

Elastin Fiber

• Reversibly stretched

• Secreted from fibroblasts

  • Precursor molecule: tropelastin

• Abundant in blood vessels, ligaments, lungs and skin

Loose Connective Tissue

• Porous, flexible

• Structure to blood vessels and nerves

• Few collagen and elastic fibers

• Highly vascularized with relatively large number of cells

Dense Connective tissue

• Many fibers

• Strength

• Fibroblast cells producing fibers

• Two types

  • Irregular

  • Regular

Specialized connective tissue

• Blood

• Cartilage

• Adipose

Blood

Very fluid ground substances with little to no extracellular fibers

Cartilage

• Structural support for other tissues

• Perichondrium

• Chondrocyte

• Interstitial growth

• Appositional growth

• no blood vessels

Perichondrium

thin membrane

Chondrocyte

cells responsible for producing matrix

• found in lacunae

Interstitial growth

growth within that results in an increase in length

Appositional growth

addition of a new layer between cartilage and perichondrium increases thickness

Adipose Tissue

• Adipocytes

• Triglyceride storage

• Highly vascularized

• Located around critical organs

• Endocrine organ: adipokines

• Insulation

Cartilage

Large amounts of extracellular fibers or matrix

• Densely packed

Types of Bone

Long,Short, Irrgular, flat

Types of Bone Tissue

Compact, Spongy

Compact Bone Tissue

• Dense

  • Osteon

• Found on the outside of bones

Spongy Bone Tissue

• Bone arranged in the small structures' spicules and trabeculae

• Help in resisting stress to bone

Spicules (bone structure)

elongated cylindrical structures

Trabeculae (bone structure)

long, flattened structures

Long Bone

• Bone growth occurs at epiphyseal plate (growth plate) or appositional growth (between periosteum and compact bone)

• Osteoblast

• Osteoclast

Osteoblast (long bone)

populations found between periosteum and bone

Osteoclast (long bone)

populations found under endosteum

Osteoblast

• Bone cell precursor

• Bone matrix production

• Divide

Osteocyte

• Mature osteoblast (mature bone cell)

• Bone matrix production

• Reside in lacunae (surrounded by the bone matrix)

Bone Matrix Production and Maintenance

Osteoblast and Osteocyte

Bone Resorption

Osteoclast

Osteoclast

• Bone resorption (breakdown)

• Mutli-nucleated cells that are formed from the fusion of cell of the monocyte macrophage lineage

Osteon

• Osteocytes

• Cylindrical (oriented parallel to

  the long axis of the long bone)

• Haversian canal

Osteocytes

ocated in lacunae

Haversian canal

contains blood vessels to provide blood flow to the cells in the osteons

contract

The major organelles within a muscle will always have the ability to ______ due to the myofibril

Avascular

lacking blood vessels

Smooth muscle

involuntary, non-striate= extremely elastic and pliable, single centrally located nucleus (1 per cell)

Cardiac Muscle

involuntary, striated, highly vascularized, one or two nuclei per cell, intercalated discs

(Can’t regen it’s self)

Skeletal Muscle

voluntary, striated, multi-nucleated=cells merge together, varying metabolic characteristics, bulk (35-65%) of carcass weight

(can repair and regen)

What are the horizontal lines?

striations

Origin

the part of the muscle that does not move during contraction

insertion

moves towards the origin during contraction

Origin, insertion

effect the speed of an contraction

push, contract

Muscle does not ____ anything it only _____

myofibril

The major organelles within a muscle will always have the ability to contract due to

Epimysium

• Outermost layer of connective tissue

  • Surrounding outside of the muscle and organ

• Strong piece of connective tissue

• provides avenues for nerves and blood vessels to enter and exit muscles

Perimysium

Conective tissue that surrounds the fascicle

Endomysium

• connective tissue surrounding myofibers

• major connective tissue component responsible for meat tenderness and changes with age

• immediately adjacent to the muscle cell membranes

Sarcolemma

is an cell membrane (made out of a phospholipid by layer) and not a connective tissue

sarcomere

smallest contractile unit of muscle

• Made up of actin and myosin along with other structural and regulatory proteins

  • Like the endoplasmic reticulum that is made up of lipids?

  • Web like for increased surface area

    • Different for each muscle type, due to each one having different needs

Function of Satellite cells

Detect damage

Adipose tissue

• Specialized connective tissue

• Intramuscular Fat (marbling): Deposited within the muscle

Hyperplasia (muscle growth)

increase in number of fibers

Hypertrophy (muscle growth)

increase in size of existing fibers (bigger)

Atrophy

decrease in size

Muscle stem cells

capable of proliferating, differentiation, and fusing w. muscle fibers, contributing more than 95% of total myonuclei in mature myofibers

Satellite Cells Location

between the basement membrane and sarcolemma of myofibers

Glycolic and Oxidated

Major types of energy metabolism

Glycolic 

• Strong and quick contractions, fatigable

• White because=No mitochondria? So little need for oxygen?

• ADP, ATP, glycolysis

Oxidated

• Terminal electronic receptor= oxygen

• Comes from krebs cycle

• Hemoglobin (red color) bound

• Transports oxygen into muscle and to myoglobin => to the mitochondria as thermal electron receptor

White muscle

speed and contraction but limited amount, short distance

Red muscle

oxygen based, longer times, fatigue resistant, greater need for ATP

Difference in muscle fiber type?

Will effect muscle turn over

Why is there more fat in the muscle of Breast verses Thigh?

• You don’t deposit fat in glycolic muscles (no mitochondria)

• The breast use oxidated muscle and thigh use glycolic

Tonic

nerve is moving all the time

Contraction

slower like waves (phasing contract and relax)

Basement membrane

structure made up of interwoven fibers connecting the endomysium to the sarcolemma

Nuclei

multinucleated due to large size of myofiber to regulate cellular functions (multiple nuclei)

Sarcoplasm

cytoplasm of myofiber

Myofibril

the unique microfilamentous organelles of myofibers

How does it know for the nerve to release Action Protentional?

• The T tubule, made up of cell membrane where the AP goes into the cell to the terminal cisterna which creates the release of calcium

• Calcium is needed for contraction

Calcium

needed for contraction

T-tubules

small invaginations of the sarcolemma surrounding the myofibrils at the A-I band junction

Sarcoplasmic reticulum (SR)

development of the endoplasmic reticulum extending between two T-tubules; Calcium storage

• Traffic things out of the cells (transport)

Sarcomere

• Smallest contractile unit of muscle

  • made up of actin and myosin along with other structural and regulatory proteins

I band

• Major protein: actin

• how to length

A band

Primary protein: myosin