Lesson 14 - Body Tissue Flashcards
Cell Junctions
Connects cells together and three types
Gap Junctions
Tight junctions
Desmosome -adhering junctions
Tight junctions
Allows no movement between cells. Only way is through cell
ex: gut, kidney, skin, blood-brain barrier
Gap junctions
Allows for movement of ions
-transmisson of charge
ex: heart, gut
Desmosomes
Structural junction
-with standstress by preventing pulling apart of tissue
ex: Skin, heart, uterus
Tissues
Cells with similar structure and function
4 types:
-Epithelial
-Connective tissue
-Nerve
-Muscle
Function of Epithelial Tissue
Covering sheets
- everything has epithelial lining and skin
Glands
-exocrine - secrete into duct (sweat and oil glands)
-endocrine - secretes hormones into blood
Functions:
-Protection (skin)
-Absorption, secretion (glands)
- ion transport/diffusion (membranes)
-filtration (membranes)
-forms slippery surface (mucus layers)
Types of Epithelial Tissue
Simple vs Stratified
-Single layer vs multi layered
Shape: Cuboidal vs columnar cells
- cube vs columns
ex: gut
Squamous cell
-Flattened
ex: lungs
Simple Epithelium (1)
Simple Squamous epithelium
(single layer squish cell)
areas subject to little wear and tear
-adapted for diffusion and filtration
ex: lung alveoli
Stratified Epithelium (2)
Stratified squamous epithelium
(many layer squish cell)
-protects areas of wear and tear
-defend against microbes
ex: outer layer of skin, lining of mouth
Transitional Epithelium
(can change shape)
contains cells that can change shape
in areas subject to stretching
Ex; bladder
Glands
Specialized epithelial cells
exocrine glands
- secretes substances into ducts
ex: sweat glands
endrocrine glands (ductless)
-secretes hormones into blood
ex: thyroid
Paracrine glands (endocrine but close by)
-secretes of short distances, to cells around
Unicellular exocrine glands (goblet cell)
Goblet cell makes mucin
Mucin+water=mucus
-protects and lubricates many internal body surfaces
Duct classification
Simple vs Compound (complex)
Variety of ducts, more then one branch= compound
Classes of connective tissue and function
Most diverse and abundant tissue
Main classes:
Connective tissue
Cartilage
Bone tissue
Blood
Fat
Different structure same func
Function: binds together and supports/strengthens
protects and insulates internal organs
compartmentalizes muscle
Connective Tissue Proteins
Collagen - stuff seen in tendons
Elastin - stretchy in Lungs
Ratio of collagen and Elastin determines function
Structural elements of connective tissue
Extracellular matrix
-collagen and elastin fibers
-viscous, gel like ground substance
-cushions and protect body (made up differently depends on where is)
difference in structure properties due to: cell types and different composition of matrix
Connective tissue Proper
Two subclasses
-lose connective tissue (areolar, adipose)
-dense connective tissue (regular vs irregular)
Loose connective tissue: Areolar
Everywhere, filler (chicken goop)
Gel like matrix with all three fibers
Contains:
fat cells
white blood cells
mast cells
fibroblasts
Underlines epithelial tissue
-surrounds blood vessels and organs
- borders all other tissues in the body
Dense irregular connective tissue
Irregularly arranged collagen and elastin
Withstands pulling/tension in every direction (can pull on skin and not pull apart)
Location:
-skin
-gut
-fibrous capsules of joints and organs
Dense regular connective tissue
Know which way stress is coming from
Parallel collagen fibres (too withstand stress)
-Some elastin
-Poorly vascularized
Muscle and Bone attachments
Withstands stress (in 1 direction)
Eg. Tendons, ligaments
Knee joint, hit from side bad
Specialized Connective Tissues
Serve Special Functions
Bone:
-forms the skeleton
* Spongy vs compact
Blood: transports materials such as
glucose and Oxygen (primarily matrix)
fluid matrix of
* plasma (fluid)
* red blood cells
* white blood cells
* platelets
Bone types
Compact bone:
Harder – haversian systems
* Yellow bone marrow (mostly
fat) in marrow space
Spongy bone:
* Spaces may contain red bone
marrow
Bones Are the Hard Elements of
the Skeleton
Bone is made 10% cells and 90% matrix
The extracellular matrix contains:
-Calcium and phosphate
-Collagen
-Proteins
-Water
Cells:
Osteoblasts (make bone)
Osteoclasts (resorb bone)
Osteocytes (mature cells)
Specialized Connective Tissues
Serve Special Functions
Cartilage:
- transitional tissue from which bone develops
maintains shape of certain body parts (nose, ears)
cushions vertebrae (vertebral disks), lines joint cavities
Adipose tissue:
-fat cells
functions in insulation, protection, and energy storage
Cartilage lends support
Provides structure and support under compression
Types:
Fibrocartilage (harder, protection)
* Intervertebral disks between vertebrae
* Menisci in knee joints
Hyaline (in the end of bones)
* Covers and protects ends of long bones in joints
Elastic cartilage
* Flexible, outer ear, tip of nose
Muscle tissue
Contractile
-Force and movement
Three types:
Cardiac - heart (striated)
Smooth - gut (striated)
Skeletal - on skeleton
Skeletal muscle tissue
-Voluntary – moves skeleton
Cardiac muscle tissue
- Heart – pacemaker controlled
Smooth muscle tissue
-Involuntary – eg. Gut, blood vessels
Nervous tissue
Signal transmission:
Brain, Nerves, spinal cord
-Transmit electrical signals
Contains two types of cells
* Neurons—excitatory cells
* Supporting cells (neuroglial cells)
Tissue repair
Regeneration
- Of damaged site with same
type of tissue
Fibrosis
- Proliferation of scar tissue (extra connective tissue)
- Organization
Clot is replaced by granulation tissue
Capacity for Regeneration
Good to excellent:
* ET, bone CT, areolar CT, dense irregular CT, and blood forming CT
Moderate:
* Smooth muscle
Weak: (tissue itself, low blood supply)
* Skeletal MT, cartilage, dense regular CT
None or almost none:
* Cardiac MT, Nervous Tissue
Heart attack, can’t regerante tissue
The Tissues Throughout Life
With increasing age:
-Skin thin (wrinkles)
-Collagen decreases (80 yr old lost 50% of muscle)
- Bones, muscles, and nervous tissue begin to atrophy
- Poor nutrition and poor circulation lead to poor health of tissues
- Decreased healing
