Lecture 15 Flashcards
What are tissues
Groups of cells with a similar structure and function
4 primary tissue types
- Epithelial
- Connective
- Muscle
- Nervous
What is epithelial tissue
Sheet of cells that covers a body surface or lines a body cavity
Two forms of epithelial tissue occur in body :
- Covering and lining epithilium
- Glandular epithelium
Covering and lining epithelium
Forms outer layer of skin, lines open cavities of urogenital/digestive/respiratory syst, covers walls and organs of closed ventral body cavity
Glandular epithelium
Found in glands of body
Epithelial tissues functions
- Protection
- Secretion
- Absorption
- Gas exchange
- Filtration
First epithelial distinguishing characteristic (cells)
Cells that make is are closely packed with very little intracellular space
2 epithelial dis char (surface)
Free (apical) surface exposed to enviro or internal chamber or passageway
3 epithelial dis char (blood vessels)
Absence of blood vessels.Bc of avascular condition, nourished by substances diffusing from bv in underlying connective tissue
4 epithelial dis char (connective tissue)
Always overlies connective tissue whose rich blood supply nourishes epithelial cells
5 epithelial dis char (replacement)
Continual replacement/regeneration of epithelial cells (damage or lost at exposed surface)
Some (not all) epithelial cells can
Secrete chemical products (may be organized as multicellular glandular structures)
Epithelia classified based on
Nb of cell layer and cell shape
Epithelial tissue nb of cell layers classification
Simple (one layer)
Stratified (multiple layers)
Epithelial tissue cell shape classification
Squamous (flat looking)
Cuboidal (cube-like)
Columnar (column like)
Connective tissues
Found everywhere in the body to connect body parts
includes the most abundant and widely distributed tissues
6 types of connective tissues
- Areolar
- Adipose
- Tendon/Ligament
- Bone
- Cartilage
- Blood
Three branches of connective tissues
Proper, supportive, fluid
Two types of proper connective tissues
Loose (areolar and adipose), dense (tendon and ligament)
Two supportive connective tissues
Bone and cartilage
Fluid connective tissue
Blood
Structure of areolar tissue
Open spaces (areola), fibres loosely arranged ->space between them
Location of areolar tissue
Most widely distributed
1. Between skin and muscles
2. Around blood vessels and nerves
3. Fills space inside organs
4. Underlies epithelia in tissue membrane
Main functions of areolar tissue
Acts as universal packing tissue and “glue” to hold organs in place
1. Supports internal organs by supporting and packing tissue
2. Binds various structures with one another -> no dislocation
3. Provides protective framework -> keeps major structures in place
Adipose tissue functions
- Insulates body
- Protects some organs
- Site if fuel storage (fat storage)
Adipose tissue location
- Subcut tissue beneath skin
- Around internal organs (protects organs like kidneys)
- Fat “depots” include hips, buttocks, breasts, belly
Tendons/ligaments tissue
Made of collagen, play key role in body mvmt and stability
Tendons
Connects muscles to bone or other structures (eyeballs) to allow mvmt, they transmit force generated by muscle contractions
Ligaments
Connect bone to bone, usually to hold structures together, keep them stable. Limit excessive mvmt in joints
Bone tissue /osseous tissue is
Skeleton
Bone tissue main function
Protect and support
Bone tissue composed of
Osteocytes (bone cells) sitting in lacunae (cavities)
Hard calcified matrix containing many collagen fibers
Hyaline cartilage characteristic
Less hard and more flexible than bone
Most widespread type of cartilage os hyaline cartilage
Hyaline cartilage locations
Nose, trachea,
attaches ribs to breastbone,
covers ends of long bones
Entire fetal skeleton prior to birth
Blood tissue
Contains specialized cells (RBC, WBC)
Cells are in fluid prot matrix called plasma
Blood tissue functions
Transport vehicle for cardiovascular system, carries nutrients, wastes, respiratory gases, hormones
Characteristics of muscle tissues
-Specialized for contraction
- contracts or shortens to produce mvmt
- able to respond to stimuli
Three types of muscle tissues
- Skeletal
- Cardiac
- Smooth
Which muscle tissue is voluntarily controlled
Skeletal
Skeletal tissue found in/ produces
Skeletal muscles attached to bone/body mvmt or facial expressions
Skeletal muscle cells
Striations (stripes)
Multinucleate (more than one nucleus)
Cardiac muscle tissue
Involuntarily controlled, found only in heart, pumps blood through cardiac muscle cells
Cardiac muscle cells
Striations, one nucleus per cell, short branching cells , intercalated discs connects cells together
Smooth (visceral) muscle tissue
Involuntarily controlled
Peristalsis (wave like motion) is typical activity
Smooth muscle tissue location
Walls of hollow organs such as stomach, uterus, blood vessels
Smooth muscle tissue cells
No visible striations, one nucleus per cell, spindle-shaped cell
Characteristics of nervous tissues
- specialized for propagation of electrical impulses from one region to another
- 98% nervous tissue is in brain and spinal cord (central nervous system)
- two basic cell types
Two basic nervous tissue cell types
- Neurons
- Neuroglia
Neurons functionality
- Receive stimuli,
- convert them into nerve impulses,
- transmit impulses rapidly to various parts if body
Neuroglia functionality
Do not conduct impulses, help protect nervous tissues and form insulating layer around nerve fibres to help conduct electrical signals faster
The word membrane has
More than one meaning in biology
Types of membranes in biology
Plasma/cell membranes
Tissues membrane
Tissue membranes are
Layers of connective/epithelial tissues that cover outside of body, organs, internal passageways (lead to exterior), lining of moveable joint cavities
4 types of body membranes
- Cutaneous
- Mucous
- Serous
- Synovial
Cutaneous membranes refer to
Skin
What is cutaneous membrane made of
Keratinized stratified squamous epithelium (epidermis) firmly attached to thick layer of connective tissue (dermis)
Cutaneous membrane characteristic
Dry membrane exposed to air
Five major functions of integumentary system
- Protection
- Temperature maintenance
- Synthesis and storage of nutrients
- Sensory receptors
- Excretion and secretion
Integ sys protection:
Protects underlying tissues and organs from impacts/chemicals/infection, prevents loss of body fluids
Integ syst temperature maintenance
Skin maintains normal body temperature by regulating heat exchange with enviro
Integ syst synthesis and nutrients storage
Epidermis synthesizes vit D3 and stores lipids in adipose tissues
Integ syst sensory reception
Receptors detect touch, pressure, pain, temperature stimuli and relay that info to nervous syst
Integ syst excretion and secretion
Glands excrete salt water and organic wastes. Specialized glands of breasts secrete milk
Dermis composition
Mostly dense (fibrous) connective tissue and accessory structures (hair, nails, sweat glands)
Serous membranes (serosae) location
Line compartments in ventral body cavity that are closed to exterior and have two layers: visceral and parietal
Visceral layer (serous membrane)
Covers organs
Parietal layer (serous membrane)
Lines body cavity walls, creates fluid that lubricate/cushion cavities to protect organs/prevent friction during mvmt
Specific serous membranes
- Peritoneum
- Pleurae
- Pericardia
Peritoneum membrane
Covers organs in abdominal cavity
Pleurae membrane
Surrounds lungs
Pericardia membrane
Surrounds heart
Mucous membrane functions
- Absorption/secretion
- Secretion -> mucus -> thick protective fluid
- Prevents pathogens/contaminants from entering
- Prevents bodily tissue from dehydration
Synovial membranes
Layer of connective tissue that lines cavities of joints and tendons. Makes synovial fluid -> has lubricating function
Mucous membrane
-moist membrane
-some secrete protective lubricating mucous
-line all body cavities that open to exterior body surface
Sinple squamous function
When thin barrier required, for diffusion to occur better
Simple squamous location
Air sacs of lungs (gas exchange between air and blood), capillaries (nutrients and waste exchange between tissues and blood)
Stratified squamous function
Protect from abrasion, continuously shed/replaced from cells dividing and moving from underlying layer
Stratified squamous location
Outer layer of skin, moist lining of mouth, esophagus, vagina
Simple columnar function
Areas that secrete mucus and absorb substances (mucus is protective lubricating layer)
Simple columnar location
Lines gastrointestinal tract (stomach to anus), ciliated one lines uterine tubes (helps propel egg towards uterus)
Pseudostratified columnar function
Protection, secretion and mvmt of mucus if ciliated
Pseudostratified columnar location
Ciliated: lines most upper respiratory tract ex nasal cavity/trachea
Simple cuboidal function
Absorbe, filtration, secretion
Simple cuboidal location
glands/kidney tubules
