Tissues – a group of similar cells working together to perform a function Tissue Types: EpithelialConnectiveMuscularNervous

Cell Junctions- When cells are touching each other they can be joined in 1 of 3 ways: Tight Junctions – sealed together by attachment proteins so that nothing can pass between the cells (if something passes thru, it must go thru the cells not between them) Tight Junctions – sealed together by attachment proteins so that nothing can pass between the cells (if something passes thru, it must go thru the cells not between them) Desmosomes – tight junctions with extra protein reinforcement so that the cells won’t rip apart when stretch (in skin). The protein reinforcements bind the attachment proteins to the cytoskeleton of both attaching cells Desmosomes – tight junctions with extra protein reinforcement so that the cells won’t rip apart when stretch (in skin). The protein reinforcements bind the attachment proteins to the cytoskeleton of both attaching cells Gap Junctions – where the cells attach, there are small tubes connecting the two cells together so that ions can pass freely between the cells Gap Junctions – where the cells attach, there are small tubes connecting the two cells together so that ions can pass freely between the cells

Epithelial Tissue Location – lining, covering, glands Location – lining, covering, glands Examples: Examples:  Skin  Lines whole digestive and respiratory passages (mucous membranes)  Lines whole urinary system  Membranes lining spinal cord and brain (Meniges)  Lines the inside of the heart cavities  Lines the uterus, epididymis  Makes up the serous membranes (lines enclosed cavities)  Prostate gland & other glands– all cells that dump hormones into the blood

Functions: Protection (from leakage, from things getting in that aren’t supposed to) Protection (from leakage, from things getting in that aren’t supposed to) Absorption Absorption Secretion Secretion Filtration Filtration

Characteristics: Square or rectangular Square or rectangular Fit closely together (tight junctions or desmosomes) – sealed so that nothing can pass between the cells Fit closely together (tight junctions or desmosomes) – sealed so that nothing can pass between the cells Sit on a basement membranes (proteins, muscle, etc.) Sit on a basement membranes (proteins, muscle, etc.) Have a free surface that is exposed to the outside or the inside of a cavity or gland or tube (apical surface) Have a free surface that is exposed to the outside or the inside of a cavity or gland or tube (apical surface) No direct connection to blood vessels – must get nutrients by diffusion No direct connection to blood vessels – must get nutrients by diffusion

Types of Epithelium Simple Squamous – flat, 1-layer – for filtration in lungs and capillaries Simple Squamous – flat, 1-layer – for filtration in lungs and capillaries Simple Cuboidal – square – for secretion Simple Cuboidal – square – for secretion –Endocrine glands – secrete into blood –Exocrine glands – secrete into ducts Simple Columnar – tall rectangular – mucous cells that line the throat and digestive tract Simple Columnar – tall rectangular – mucous cells that line the throat and digestive tract Statified squamous – where there is a lot of abrasion – mouth, skin Statified squamous – where there is a lot of abrasion – mouth, skin Transitional – Stratified – can change shape based on amount of stretch - bladder Transitional – Stratified – can change shape based on amount of stretch - bladder

Connective Tissue – found everywhere – holds everything together Functions Functions  Protection (can cushion)  Support  Binding together

Characteristics: Some cells that aren’t connected to each other Some cells that aren’t connected to each other Surrounded by an extracellular matrix that is secreted by the cells Surrounded by an extracellular matrix that is secreted by the cells Matrix may be jelly-like, liquid, hard, fibrous Matrix may be jelly-like, liquid, hard, fibrous Has a good blood supply (except for tendons, ligaments, and cartilage Has a good blood supply (except for tendons, ligaments, and cartilage

Types of Connective Tissue: Bone – cells in a space (lacuna) surrounded by a hardened matrix made of protein and calcium with canals to connect to blood vessels Bone – cells in a space (lacuna) surrounded by a hardened matrix made of protein and calcium with canals to connect to blood vessels

Bone Tissue

Types of Connective Tissue: Cartilage (elastic and fibrous) – cells in lacunae surrounded by semi-hard matrix, cells are larger than bone cells Cartilage (elastic and fibrous) – cells in lacunae surrounded by semi-hard matrix, cells are larger than bone cells  Examples – joints, between vertebrae (discs), connecting ribs to sternum, ears, nose

Cartilage

Types of Connective Continued Dense Fibrous – few fibroblasts and many fibers made by the fibroblasts – very strong Dense Fibrous – few fibroblasts and many fibers made by the fibroblasts – very strong Examples Examples  Tendons  Ligaments  Lower layer of skin

Dense Fibrous Connective Tissue

Dense Fibrous from a Tendon

Types of Connective Tissue Continued Areolar or loose fibrous – few fibroblasts, loose network of fibers, lots of liquid space Areolar or loose fibrous – few fibroblasts, loose network of fibers, lots of liquid space Wraps around organs Wraps around organs protects organs protects organs holds organs in place holds organs in place provides fluid and nutrients to cells and absorbs waste provides fluid and nutrients to cells and absorbs waste

1. It attaches epithelial layers to underlying tissues. 2. It is a general bedding substance (stoma) in the interiors of many organs. 3. Located around blood vessels, nerves and ducts. 4. It is a packing material in spaces between tissues. C. Functions 1. It functions mechanically by: a. providing support with mobility b. increasing elasticity in tissues and organs c. providing pathways for blood vessels and nerves d. packing unused spaces in the body 2. Transport - It allows the movement of food, oxygen and wastes between capillaries and tissue cells. 3. Defense a. The ground substance of areolar tissue impedes the spread of pathogenic organisms except those which can digest the ground substance. b. Phagocytic cells in the tissue can destroy microbes. 4. Repair - The fibroblasts of areolar tissue produce new fiber and ground substance to repair damage.

Areolar Tissue Fibroblast cell Elastic Fiber Collagen Fibers

Types of Connective Tissue Continued Adipose – fat storing tissue – cells with a big oil vacuole Adipose – fat storing tissue – cells with a big oil vacuole  Insulates, cushions, lines whole body underneath skin, available for energy Reticular – fibroblasts, fibers woven into a mesh, and liquid Reticular – fibroblasts, fibers woven into a mesh, and liquid  Present in spleen, tonsils, bone marrow  Makes a bed for free cells like in lymph nodes and bone marrow and traps dead red blood cells

Adipose Tissue

Reticular Tissue

Types of Connective Tissue Cont. Blood – cells in a liquid matrix Blood – cells in a liquid matrix  Carries oxygen, carbon dioxide, nutrients, and wastes  Carries immune cells and antibodies to infected or damaged area  Carries minerals  Has lots of proteins for osmotic balance

Blood

Nervous Tissue Functions: Functions: Communicate quickly with other cells Communicate quickly with other cells Send information from the brain and spinal cord to nervous tissue, muscle tissue, glands Send information from the brain and spinal cord to nervous tissue, muscle tissue, glands Carry input from sensory receptors to the brain and spinal cord Carry input from sensory receptors to the brain and spinal cord

Characteristics of Nervous Tissue Large cell body with axons which are long extensions of cytoplasm (may be up to 3 ft.) Many of the long axons are covered in myelin (a fat) to improve conductivity Large cell body with axons which are long extensions of cytoplasm (may be up to 3 ft.) Many of the long axons are covered in myelin (a fat) to improve conductivity Cell body also has many short extensions connecting to other close nerve cells called dendrites Cell body also has many short extensions connecting to other close nerve cells called dendrites

Neuron Cell Body Dendrites Axon

Skeletal Muscle Location – attached to bones Location – attached to bones Functions – voluntary movement and temperature regulation Functions – voluntary movement and temperature regulation Characteristics: Characteristics:  Long (up to 2 inches) and cylindrical  Multinucleated  Striated  Voluntary Control

Skeletal Muscle

Cardiac Muscle Location – Heart Location – Heart Function – Involuntary pumping of blood Function – Involuntary pumping of blood Characteristics: Characteristics:  Long and cylindrical  Single nucleus  Striated  Branched  Involuntarily Controlled  Has intercalated discs (gap junctions) – ions that set off contraction spread from cell to cell quickly

Cardiac Muscle Intercalated Disc →

Smooth Muscle Location: Walls of hollow organs, glands Location: Walls of hollow organs, glands Function: Squeeze out the contents of an organ or squeeze hormones down a duct to the blood Function: Squeeze out the contents of an organ or squeeze hormones down a duct to the blood Characteristics Characteristics  Spindle-shaped  Single nucleus  No striations  Involuntarily controlled

Smooth Muscle