Tissues, Glands and Membranes

A tissue is a group of cells that have a similar structure and function A tissue is a group of cells that have a similar structure and function The microscopic study of tissues is called histology The microscopic study of tissues is called histology

Epithelial Epithelial Connective Connective Muscle Muscle Nervous Nervous Four Types of Tissue

Epithelial Tissue

Epitihelial – “ Covering Lining” Epitihelial – “ Covering Lining” Covers internal and external surfaces throughout the body Covers internal and external surfaces throughout the body Three parts: free surface Three parts: free surface basement membrane basement membrane very little extracellular space very little extracellular space

Functions of the epithelial cell Functions of the epithelial cell Protects the underlying structures- for example the skin Protects the underlying structures- for example the skin Acts as a barrier to certain substance- for example water, toxic molecules, and microorganisms Acts as a barrier to certain substance- for example water, toxic molecules, and microorganisms Also allows the passage of certain substances – for example oxygen and carbon dioxide Also allows the passage of certain substances – for example oxygen and carbon dioxide Secretes substance – for example secretions from sweat glands Secretes substance – for example secretions from sweat glands Absorbs substances – for example vitamins, minerals Absorbs substances – for example vitamins, minerals

Classified according to the number of layers and the cell shape Classified according to the number of layers and the cell shape #of layers Cell shape #of layers Cell shape Simple (one layer) Squamous Simple (one layer) Squamous Cuboidal Cuboidal Columnar Columnar Pseudo stratified Columnar Pseudo stratified Columnar Stratified Squamous Stratified Squamous Keratinized Keratinized Non Keratinized Non Keratinized Transitional Roughly cuboidal to columnar Transitional Roughly cuboidal to columnar when not stretched,squamous when not stretched,squamous when stretched when stretched

The structure relates to the function The structure relates to the function Simple epithelium- found in movement epithelium Simple epithelium- found in movement epithelium - gasses across wall of alveoli - gasses across wall of alveoli - filtration of fluid across kidneys - filtration of fluid across kidneys - secretion of glands - secretion of glands - nutrient absorption - nutrient absorption

Sratified epithelium Sratified epithelium well adapted for its protective function well adapted for its protective function as outer layers are damaged, they are replaced by deeper cell layers as outer layers are damaged, they are replaced by deeper cell layers Found where abrasions may occur, such as skin, anal canal and vaginal canal Found where abrasions may occur, such as skin, anal canal and vaginal canal

Differences also reflected in the cell shape Differences also reflected in the cell shape Flat and thin cells – for diffusion in lungs and filtration in kidneys Flat and thin cells – for diffusion in lungs and filtration in kidneys Cuboidal or columnar cells are cells with major functions of secretion or absorption. They are larger because they contain more organelles for all the functions they must perform e.g. columnar cells of the stomach lining have secretory vesicles that secrete mucus. Cuboidal or columnar cells are cells with major functions of secretion or absorption. They are larger because they contain more organelles for all the functions they must perform e.g. columnar cells of the stomach lining have secretory vesicles that secrete mucus.

Free Surface of the cell

Cell Connections Tight Junctions Desmosoes Hemidesmosomes Gap junctions

Glands Glands- A gland is a multicellular structure that secretes substances on to a surface, into a cavity or into the blood Glands- A gland is a multicellular structure that secretes substances on to a surface, into a cavity or into the blood Most are made of epithelial cells Most are made of epithelial cells

Types of Glands Exocrine- glands that have ducts Exocrine- glands that have ducts - simple- no branches - simple- no branches -compound- branches -compound- branches ends- 1-tubular ends- 1-tubular straight tubular straight tubular coiled tubular coiled tubular 2- acinar/ alvoelar or saclike 2- acinar/ alvoelar or saclike 3- both tubuloacinar 3- both tubuloacinar

Types of Exocrine Glands Types of Exocrine Glands

Endocrine-have no ducts and empty their secretions directly into the blood Endocrine-have no ducts and empty their secretions directly into the blood Secretions are called hormones and these hormones are carried to other parts of the body by the blood Secretions are called hormones and these hormones are carried to other parts of the body by the blood Endocrine Glands

Connective Tissue Connective Tissue

Connective Tissue Connective Tissue structure – large amounts of extracellular materials that separate cells from one another Connective Tissue structure – large amounts of extracellular materials that separate cells from one another This extracellular matrix is divided into three parts: This extracellular matrix is divided into three parts: -protein fibers -protein fibers - ground substance consisting of non fibrous protein and other molecules - ground substance consisting of non fibrous protein and other molecules - fluid - fluid

Connective Tissue Matrix

Protein Fibers - Collagen Fibers- resemble microscopic ropes, flexible but resist bending - Collagen Fibers- resemble microscopic ropes, flexible but resist bending - Reticular Fibers- very fine short collagen fibers that branch to form the supporting network - Reticular Fibers- very fine short collagen fibers that branch to form the supporting network - Elastic Fibers- structure similar to coiled metal bed springs - Elastic Fibers- structure similar to coiled metal bed springs but after being stretched, elastic fibers recoil to their original shape but after being stretched, elastic fibers recoil to their original shape

Connective Tissue Matrix

Ground Substance Ground Substance Ground Substance is the shapeless background against which cells and collagen fibers are seen in the light microscope Ground Substance is the shapeless background against which cells and collagen fibers are seen in the light microscope Made up of highly structured molecules Made up of highly structured molecules Consists of Proteoglycans (proteins and carbohydrates that trap water) Consists of Proteoglycans (proteins and carbohydrates that trap water)

Connective Tissue Matrix

Cells of the matrix

How Do We Name Connective Tissue ? According to Their Functions According to Their Functions examples: examples: Blast- produces the matrix Blast- produces the matrix Cyte – maintains the matrix Cyte – maintains the matrix Clast-break down the matrix for Clast-break down the matrix for remodeling remodelingMacrophage Mast Cell

Functions of the Connective Tissue Encloses and Separates Encloses and Separates Connecting tissue to one another Connecting tissue to one another Supporting and Moving Supporting and Moving Storing Storing Cushioning and insulating Cushioning and insulating Transporting Transporting Protecting Protecting

Classification of Connective Tissue Loose (areolar) Loose (areolar) Adipose Adipose Dense Connective Tissue Dense Connective Tissue - Dense collagenous connective - Dense collagenous connective A) Collagen arranged in same direction A) Collagen arranged in same direction B) Collagen arranged in many directions B) Collagen arranged in many directions Dense elastic connective tissue Dense elastic connective tissue A)Elastic arranged in many directions A)Elastic arranged in many directions b) Elastic fibers arranged in same direction b) Elastic fibers arranged in same directionCartilage Hyaline Hyaline FIbrocartilage FIbrocartilage Elastic Cartilage Elastic Cartilage Bone Bone Blood Blood

Loose Areolar Tissue -mostly collagen, few elastic and widely separated from each other Produced by the fibroblast This is the tissue that fills in the spaces Loose Areolar Tissue -mostly collagen, few elastic and widely separated from each other Produced by the fibroblast This is the tissue that fills in the spaces

Loose Connective TISSUE

Adipose Tissue Has very little collagen and elastic fibers Has very little collagen and elastic fibers Large cells filled with lipids Large cells filled with lipids Pads of protection and thermal insulation Pads of protection and thermal insulation

Dense Connective Tissue Densely packed fibers that produced by the fibroblast Densely packed fibers that produced by the fibroblast Dense Collagenous- mostly collagen Dense Collagenous- mostly collagen tendons, ligaments, capsules around organs tendons, ligaments, capsules around organs same direction in tendons, different in organs same direction in tendons, different in organs Dense Elastic Tissue- abundant elastic fibers among collagen fibers Dense Elastic Tissue- abundant elastic fibers among collagen fibers vocal cords, walls of large arteries vocal cords, walls of large arteries

Dense Elastic

Cartilage Composed of cartilage cells or Chondrocytes Composed of cartilage cells or Chondrocytes Located in the matrix along with collagen Located in the matrix along with collagen Amongst the extracellular matrix Amongst the extracellular matrix It gives the matrix resilience It gives the matrix resilience Hyaline Hyaline Fibro Fibro Elastic Elastic

Hyaline Cartilage The most abundant type of cartilage The most abundant type of cartilage Ends of bones where they come together to form joints. It is the smooth and resilient Ends of bones where they come together to form joints. It is the smooth and resilient Surfaces that withstand repeated compression Surfaces that withstand repeated compression Costal, respiratory, and nasal cartilges Costal, respiratory, and nasal cartilges

Fibrocartilage Has more fibrous tissue than does hyaline cartilage Has more fibrous tissue than does hyaline cartilage, bundles of collagen, bundles of collagen Resists pulling or tearing Resists pulling or tearing Found in the disks between vertebrae and in some joints Found in the disks between vertebrae and in some joints

Elastic Cartilage Has elastic fibers, collagen proteoglycans Has elastic fibers, collagen proteoglycans Coiled fibers amongst bundles of collagen fibers Coiled fibers amongst bundles of collagen fibers Can recoil to its original shape when bent Can recoil to its original shape when bent External ear, epiglottis, auditory tube External ear, epiglottis, auditory tube

Bone Is hard connective tissue that consists of cells and a mineralized matrix Is hard connective tissue that consists of cells and a mineralized matrix Osteoblasts secrete the matrix called lamellae Osteoblasts secrete the matrix called lamellae osteocytes are located in lacune osteocytes are located in lacune The Osteon ( Haversion system) consist of central canal with blood vessels, osteocytes and lamellae The Osteon ( Haversion system) consist of central canal with blood vessels, osteocytes and lamellae

Haversion System/Osteon Haversion System/Osteon

Blood Here the matrix is a liquid which enables the blood to move through the vessels to carry nutrients and other materials Here the matrix is a liquid which enables the blood to move through the vessels to carry nutrients and other materials

Muscle Tissue Main Characteristic is its ability to contract, making movement possible Main Characteristic is its ability to contract, making movement possible Contractile proteins in the muscle cells themselves, called actin and myosin Contractile proteins in the muscle cells themselves, called actin and myosin Muscle cells are called muscle fibers because they resemble tiny threads Muscle cells are called muscle fibers because they resemble tiny threads

Three Types of Muscle Tissue Skeletal Muscle Skeletal Muscle Cardiac Muscle Cardiac Muscle Smooth Muscle Smooth Muscle

Skeletal Muscle Normally thought of as “muscle” Normally thought of as “muscle” Meat of animals, 40% of persons body weight Meat of animals, 40% of persons body weight Attaches to the skeletal system and enables body movement Attaches to the skeletal system and enables body movement Long and cylindrical cells with several nuclei per cell Some cells are the entire length of the muscle Striated, Striated, Vountary Vountary

Smooth Muscle Forms the hollow walls of the organs and is also in the skin and eyes Forms the hollow walls of the organs and is also in the skin and eyes Movement of food and emptying of the Urinary Bladder Movement of food and emptying of the Urinary Bladder Involuntary Involuntary Tapered at each end, have a single nucleus and are not striated Tapered at each end, have a single nucleus and are not striated

Cardiac Muscle Muscle of the heart and is responsible for Muscle of the heart and is responsible for Involuntary control Involuntary control Cylinder in shape and shorter than skeletal Cylinder in shape and shorter than skeletal Striated and one nucleus Striated and one nucleus Connected by intercalated disks Connected by intercalated disks

Classification of Muscles Skeletal Smooth Cardiac Skeletal Smooth Cardiac Voluntary involuntary involuntary Voluntary involuntary involuntary Striated not striated striated Striated not striated striated >1nuclei 1 nuclei 1 nuclei >1nuclei 1 nuclei 1 nuclei

Nervous Tissues Forms the brain, spinal cord and nerves Forms the brain, spinal cord and nerves Coordinates and controls many body activities Coordinates and controls many body activities Conscious and unconscious Conscious and unconscious Awareness, emotion, reasoning Awareness, emotion, reasoning Communicate through action potentials Communicate through action potentials Cell= neuron or nerve cell responsible for conduction of action potentials Cell= neuron or nerve cell responsible for conduction of action potentials Neuron – cell body, dendrites and axons Neuron – cell body, dendrites and axons Neuroglia surrounding support cells Neuroglia surrounding support cells

Neurons and Glial cells

Membranes Serous Membranes Serous Membranes simple squamous epithelium resting on delicate layers of loose connective tissue simple squamous epithelium resting on delicate layers of loose connective tissue cavities and cover the organs inside these cavities cavities and cover the organs inside these cavities secretes serous fluid which lines the cavitites secretes serous fluid which lines the cavitites prevents trauma and damage prevents trauma and damage

Membranes Pleural- lungs - Pleuritis Pleural- lungs - Pleuritis Pericardium- heart - Pericarditis Pericardium- heart - Pericarditis Peritoneal other - Peritonitis Peritoneal other - Peritonitis

Other Membranes Cutaneous Cutaneous Synovial Synovial Periosteal Periosteal