Chapter 4 - Tissues Flashcards
Define tissues and explain it’s uses
Definition: Groups of similar cells that perform a common function.
Uses: holds body structures together providing the body with its shape and gives it the ability to move.
Name the 4 types of tissues
Epithelial, connective, nervous, and muscular
What is the Epithelial tissue?
Covers the body’s surface, lines the body cavities and many of the organs, and forms certain glands.
What is epithelial tissue classified by?
Shape and layers as well as glandular epithelium
What are the three cell shapes?
Squamous, cuboidal, and columnar
Flat and plate-like cells.
Squamous
Cube-shaped cells that contain more cytoplasm than squamous cells.
Cuboidal
High and wide shaped cells that are tall and cylindrical.
Columnar
Epithelia may appear as single or multiple layers called…
Simple: every cell touches the basement membrane
Stratified: some cells stack on top of other cells and the upper layers of cells don’t touch the basement membrane.
Glandular epithelium
A collection of epithelial cells that specializes in secretion of a particular substance.
Exocrine glands: secrete tears, sweat, or gastric juices into ducts. The ducts then empty into a body surface or inside a body cavity.
Endocrine glands: ductless glands. Secret hormones into blood. Pituitary, thyroid, and ovaries.
Simple squamous epithelium; how many layers? Functions? Location?
Layers: Single layer of flat, scale-like cells.
Function: Allows for ready diffusion or filtration because of thinness
Location: alveoli and lining of blood and lymphatic vessels
Simple cuboidal epithelium: layers? Functions? Location?
Layers: single layer of cube-like cells
Function: secretes and absorbs
Location: ducts and tubules of many organs, including the kidneys
Simple columnar epithelium: layers? Functions? Location?
Layers: single layer of columnar cells
Functions: participates in absorption, secretes mucus by goblet cells (modified columnar cells containing secretory vesicles that produce large quantities of mucus.
Location: lines intestines
Pseudostratified columnar epithelium: layers? Functions? Locations?
Layers: single layer of irregularly shaped columnar cells; cells of different heights with nuclei at different levels makes it appear stratified
Function: provides protection, secretes mucus
Location: lines trachea, large bronchi, and nasal mucosa
Stratified squamous epithelium: layers? Functions? Locations?
Layers: multiple layers (stronger than simple epithelia). Most widespread epithelium in the body
Functions: resists abrasion and penetration by pathogens, some contain keratin (epidermis) some do not (mucous membranes)
Location: epidermis of the skin, esophagus, vagina
Transitional epithelium: layers? Functions? Locations?
Layers: multiple layers, when stretched, cell layers decrease and cell shape changes from cuboidal to squamous
Function: stretches to allow filling of urinary tract
Location: urinary tract
Connective tissue
Connect the body together
7 types of connective tissue
Dense fibrous, cartilage, reticular, areolar, blood, bone, adipose
Fibrous connective tissue
May be loosely arranged, as in connective tissue, or tightly packed, as in dense connective tissue.
Types of loose connective tissue
Areolar, adipose, reticular
Areolar tissue
- consists of collagen and elastin fibers in a soft, gel-like matrix
- connects many adjacent structures in the body
- lies underneath almost all epithelia
- surrounds blood vessels, nerves, the esophagus, and trachea
Adipose tissue
- dominated by fat cells
- forms supporting, protective pads around the kidneys and various other structures
- acts as a storage depot for excess food
- helps insulate the body to conserve body heat
Reticular tissue
- consists of a loose network of reticular fibers and cells
* forms the framework of the spleen, lymph nodes, and bone marrow
Dense connective tissue
Consists of closely packed collagen fibers, forms tendons and ligaments.
Cartilage
Also called chondrocytes, it has a rubbery, flexible matrix. Contains no blood vessels. Receives nutrients by diffusion- when damaged its heals slowly or not at all.
3 types of cartilage
Hyaline, elastic, fibrocartilage
Hyaline cartilage
Found at the end of moveable joints, at the point where the ribs attach to the breastbone, the larynx, and the supportive rings around the trachea.
Forms much of the fetal skeleton
Elastic cartilage
Provides flexible support to the external ear and the epiglottis
Fibrocartilage
Forms the discs between the vertebrae and in the knee joint because this cartilage resists compressions and absorbs shock
Bone
Type of tissue, also known as osseous tissue composed of osteocytes embedded in a matrix of colleges fibers and miners salt crystals (that are responsible for the hardness of the bones)
Give the body structure, provide support, and offer protection to internal organs such a as the brain. Attachment point for muscles, making movement possible. The matrix of bone serves as storage for calcium.
Blood
Fluid composed of various types of blood cells surrounded by plasma. It transports cells and dissolved substances from one part of the body to another.
Nervous tissue
High degree of excitability and conductivity. Found in the brain, spinal cord, and nerves.
Two types of nerve cells
Neurons-the nuts that conduct nervous impulses
Neuroglia-protect and assist neurons
Soma
large body of cells inside each neuron
Contains the nucleus of the nerve cell as well as the organelles
Dentrites
Short processes Receive impulses from other cells then transmit to the soma
Axon
A single long nerve fiber transmits signals to other cells.
Muscle tissue
Elongated cells that contract in response to stimulation. Three types. Skeletal, cardiac, smooth
Skeletal muscle
Long thin cells (muscle fibers) called striated or voluntary (light and dark bands gives it striped or striated appearance and we can move it voluntarily).
- most attached to bone
- controls breathing, speech, urination, and facial expressions and makes movement possible
Cardiac muscle
Only in the heart. Involuntary
Smooth muscle
Long, spindle-shaped cell lacks striped pattern; is stimulated by autonomic nervous system, not voluntary, lines the walls of many organs; controls diameter of blood vessels.
Tissue repair
Two ways; regeneration or fibrosis
Regeneration
Occurs when damaged cells are replaced with same type of cells. Cuts and scrapes heal by regeneration
Fibrosis
When damaged tissue is replaced by scar tissue-compared mainly of collagen; binds wounds but doesn’t restore normal function.
Severe cuts or burns.
Steps in Tissue repair
- Bleeding wound
- Blood clot, scan, WBC ingest bacteria and cellular debris.
- Surrounding healthy tissue sends nutrients. Newly formed tissue called granulation tissue forms. Fibroblasts inside granulation tissue secretes collagen forming scar tissue inside the wound.
- Generates new epithelial cells, migrate underneath the scab.
Membranes
Thin sheets of tissue
Line body cavities, cover body surfaces, and separate organs. Some
Secret lubricants to reduce friction. Heart beats, bending joints.
3 types of epithelial membranes
Mucous, cutaneous, serous.
1. Mucous lines body surfaces that open directly to body’s exterior.
2. Cutaneous; skin
3. Serous; simple squamous; line closed body cavities and also cover many of the organs in those cavities; 3 types
• pleura-surrounds lungs & lines thoracic cavity
• pericardium-surrounds the heart
• peritoneum- lined ab cavity
Synovial membrane
Lines joints
