Chapter Four Flashcards
1
Q
What are the four main tissue types?
A
- Epithelial
- Connective
- Muscular
- Nervous
2
Q
Epithelial tissue
A
- Covers body surfaces and lines hollow organs, body cavities,and ducts
- Also forms glands
- Form coverings and linings of external and internal spaces
- cells arranged in sheets
- Densely packed
- many cell junctions present
- attach to basement membrane
- avascular
- cells divide frequently
3
Q
Connective Tissue
A
- protects and supports the body and its organs
- binds organs together
- stores energy, and helps the body with immunity
4
Q
Muscular Tissue
A
- made of cells that are specialized for contraction and generation of force
- In the process, muscular tissue produces heat
5
Q
Nervous tissue
A
- detects changes inside and outside the body
- conducts nerve impulses that activate muscular glandular tissue
6
Q
What are the five types of cell junctions?
A
- Tight Junctions
- Adherens Junctions
- Desmosomes
- Hemidesmosomes
- Gap junctions
7
Q
Tight Junctions
A
- Sometimes called “occluding junctions”
- Prevent small molecules from passing through intercellular spaces
- Found near the outer surface cells
- Cells of tissues that line the stomach and intestines gave many tight junctions
- Inhibits the passage of substances between cells
- Prevents the contents of these organs from leaking into the blood
8
Q
Adherens Junctions
A
- contain a “belt” of proteins that form a plaque on the inside of the plasma membrane
- The proteins from one cell attach to the proteins of another cell
- Adherens junctions help cells resist separation when they are stretched
9
Q
Desmosomes
A
- act as “spot welds”
- like adherens junctions, but smaller
- common among the cells that make up the epidermis (skin)
- Desmosomes prevent cells from separating under tension
10
Q
Hemidesmosomes
A
- similar to desmosomes but do not link adjacent cells
- Instead, they anchor cells to a basement membrane
11
Q
Gap junctions
A
- pores created by special membrane proteins called connexons
- Function in communication between tissue cells
- Cardiac muscle cells
- Allow substances like ions and small molecules to pass between cells
- Enables nerve or muscle impulses to spread rapidly among cells
- Also allows the passage of nutrients and wastes between cells of avascular tissue
- Lens and cornea of the eye
12
Q
A
Tight junctions
13
Q
A
Adherens junctions
14
Q
A
Desmosomes
15
Q
A
Hemidesmosomes
16
Q
A
Gap junctions
17
Q
How do epithelial and connective tissues differ?
A
- Number of cells in relation to the extracellular matrix
- epithelial tissue has little to no extracellular matrix
- connective tissues have large amounts of extracellular matrix between cells
- Blood supply
- Epithelial tissues have no blood vessels (avascular)
- Connective tissues have significant networks of blood vessels
- Where it is found in the body
- Epithelial tissues are always found covering or lining body surfaces and is usually on top of connective tissue
18
Q
Basement Membrane
A
- A thin extracellular sheet that consists of two layers
- Basal lamina
- Reticular lamina
- The basal lamina is thicker and close to the epithelial cells
- secreted by epithelial cells
- contains several proteins that help keep epithelial cells attached
- The reticular lamina is close to the underlying connective tissue
- Helps anchor the basement membrane to the underlying connective tissue
- Restricts the passage of larger molecules between epithelium and connective tissue
19
Q
Simple Squamous Epithelium
A
- a single layer of thin, flattened cells
- found in air sacs of lungs, serous membranes (mesothelium), and lining blood vessels (endothelium)
- Functions in the diffusion of gases, secretion, and filtration
20
Q
Simple Cuboidal Epithelium
A
- a single layer of cube-shaped cells with centrally located nuclei
- Found in tubules of kidneys and in some glands
- functions in secretion and absorption
21
Q
Simple Columnar Epithelium
A
- A single row of elongated cells
- May contain cilia or microvilli and usually contains goblet cells (mucus)
- Found in:
- Intestines= microvilli increase the absorption of nutrients
- Stomach= goblet cells secrete mucus to protect stomach lining in acid
22
Q
Pseudostratified Columnar Epithelium
A
- cells are attached to basement membrane in a single layer
- some do not extend to the apical surface
- Can be ciliated (cilia move duct debris trapped in mucus)
- Found in respiratory tubes (trachea and bronchioles)
23
Q
Stratified Squamous Epithelium
A
- multiple layers of flattened cells
- many layers are ideal for protection against friction
- makes up the skin, and lines the mouth, throat, vagina, and anal canal
- Can be keratinized or non-keratinized
- Keratin is a hardening protein
24
Q
Stratified Cuboidal Epithelium
A
- 2-3 layers of cube-like cells
- lines the lumens of mammary glands, sweat glands, and salivary glands
- Several layers provide greater protection than single layer
25
Q
Stratified Columnar Epithelium
A
- basal layer of cells are usually shortened and irregularly shaped
- only the apical layer has columnar cells and can be ciliated
- Lines part of the male urethra and parts of the pharynx
- protection and secretion
26
Q
Transitional Epithelium
A
- Several layers of cells
- outer layer is dome-shaped when relaxed, flat when distended
- Found in the urinary bladder and portions of the urinary tract
- Function is to provide elasticity and allow organs to stretch
29
Q
Merocrine glands
A
- cells release secretions through cell membrane by exocytosis
- Ex. salivary glands and sweat glands of the skin
30
Q
Apocrine glands
A
- cells release secretions by pinching off a portion of the cell membrane
- Ex. mammary glands and ceruminous glands in ear canal
31
Q
Holocrine glands
A
- release entire cells that disintegrate to release their secretions
- Ex. Sebaceous glands of the skin
41
Q
Areolar Connective Tissue
A
- forms delicate, thin membranes throughout body (part of basement membrane for epithelial tissues)
- consists of fibers (collagen, reticular, elastic) arranged randomly
- used to attach skin to underlying tissues
- used as packing between glands, muscles, and nerves
42
Q
Adipose tissue
A
- designed to store lipids (fat) for protection and energy
- found beneath skin, around joints, and padding internal organs
- cells are called adipocytes
43
Q
Reticular Connective Tissue
A
- composed of a network of interlacing reticular fibers and cells
- provides framework for certain lymphoid tissues and organs
- spleen and lymph nodes
44
Q
Dense Regular Connective Tissue
A
- consists of densely packed collagen fibers
- very strong but lacks a good blood supply
- found as part of tendons and ligaments and as the white layer of the eyeball (sclera)
- resists pulling
45
Q
Dense Irregular Connective Tissues
A
- like dense regular CT but fibers are arranged in different directions
- Often occurs in sheets, such as fasciae (tissue beneath skin and around muscles)
- provides tensile (pulling) strength in many directions
46
Q
Elastic Connective Tissue
A
- Contains elastic fibers with fibroblasts between them
- found in lung tissue, walls of arteries, and trachea
- allows stretching and can recoil
48
Q
Hyaline cartilage
A
- Most common type of cartilage
- found at ends of bones and supports respiratory passages
- consists chondrocytes in a clear, gel-like matrix (stays in the lacunae)
49
Q
Elastic cartilage
A
- dense network of elastic fibers in EM
- More flexible than hyaline
- provides framework for external ears and epiglottis
50
Q
Fibrocartilage
A
- Tough tissue with thick bundles of collagen fivers
- provides shock-absorbing function in intervertebral discs, knees, and pelvic girdle
51
Q
Bone- connective tissue
A
- Most rigid
- EM is made up of mineral salts and collagen
- supports and protects the body and provides attachment for muscles
- Site for blood cell formation
- Osteocytes: bone cells that produce and surround themselves in the calcified EM
- Bone has a rich blood supply
- Highly vascular -→ enable rapid recovery after injury
- 2 types of bone (depends on EM)
- Compact bone: non-porous, found on outside of most bones
- Spongy bones: porous, found on inside of most bones
52
Q
Blood- connective tissue
A
- Composed of formed elements (cells) suspended in a liquid matrix called plasma
- Formed elements include:
- RBC- carry oxygen
- WBC- protection (immunity)
- Platelets- clotting
- Functions to transport substances throughout the body
55
Q
Skeletal muscle tissue
A
- found in muscles that attach to bones
- under voluntary control
- fibers contain light and dark bands- striated
- Each cell contains many nuclei
*
56
Q
Smooth muscle
A
- found in walls of hollow organs and lines blood vessels
- some contain gap junctions
- cells are spindle shaped and contain only one nucleus
- Involuntary and non-striated
57
Q
Cardiac muscle
A
- muscle that makes up the heart
- branching fibers that are connected by intercalated discs (gap junctions)
- cells contain one nucleus each
- involuntary and striated
58
Q
Nervous tissue
A
- found in brain, spinal cord, and nerves
- two cell types:
- Neurons- conduct nerve impulses
- Neuroglia- protect and support neurons
