Chapter 5 - Tissue

Question 1

Tissue:

Answer 1

a group of cells that are not identical but are similar in structure and perform a common function

Question 2

4 Types of Tissue

Answer 2

• Epithelial: protect, secrete, absorb, excrete
  
  • Connective: bind, support, protect, fill spaces, store fat, produce blood cells
  • Muscle: generate forces for movement
  • Nervous: conduct impulses for coordination, regulation, integration and sensory reception

Question 3

Intercellular Junctions

Answer 3

the site of union between two cells tightly packed together in tissues which connect cell membranes

Question 4

Tight Junctions

Answer 4

membranes of adjacent cells converge and fuse
○ Typically joins cells that form sheetlike layers
○ e.g. small intestine lining

Question 5

Desmosome Junctions

Answer 5

rivets or spotwelds skin cells enabling them to form a reinforced structural unit
○ E.g. Cells of outer skin layer

Question 6

Histology

Answer 6

the microscopic study of tissues

Question 6

Gap Junctions

Answer 6

cells linked by channels to the cytoplasm of adjacent cells allowing ions, nutrients and small molecules to pass through
○ E.g. muscle cells of heart and digestive tract

Question 7

Simple Squamous

Answer 7

• Consists of a single layer of thin flattened cells tightly packed
  
  • Consists of thin and broad nuclei
  • Substances can pass easily through making them common sites for diffusion and filtration
• Line alveoli and forms walls of capillaries

Question 8

Simple cuboidal

Answer 8

• Single layer of cube shaped cells
  
  • Centrally located and spherical nuclei
  • Lines the thyroid gland, covers ovaies and lines kidney tubules
    Functions in the formation of urine in kidneys and secretes glandular products in glands

Question 9

Simple Columnar

Answer 9

• Single layer of cells that are rectangular in shape
  
  • Nuclei are typically all at the same level near the basement membrane
  • Can be either ciliated or nonciliated extending from apical surface
  • Lines the digestive tract (stomach, SI, LI)
  • Protects underlying tissue due to its thickness and secretes digestive fluids and aids in absorption of nutrients
    ○ Have microvilli if they are absorbing cells

Question 10

Pseudostratified Columnar

Answer 10

• Appear stratified because nuclei are at different levels but is a single layer of columnar cells with some not all reaching the apical surface
  
  • Have cilia and have goblet cells scattered throughout the tissue which secrete mucus
  • Lines the passage of respiratory system where it traps molecules in the mucus and then the cilia move it away

Question 11

Stratified Squamous

Answer 11

• Many layers of cells wehre the top ones are thin, with the bottom ones appearing almost cuboidal or columnar
  • Found in the epidermis skin layer and as they are pushed outwards the cells accumulate keratin proteins which harden the cells and die
  • Produces a tough dry covering which protects the material underneath
    Lines oral cavity, vagina, anal canal and in these parts its not keratinized but keeps the places soft and moist

Question 12

Stratified Cuboidal

Answer 12

• 2-3 layers of cuboidal cells
  
  • Provide lots of layers of protection
    Found in the ducts of mammary, salivary and sweat glands and the pancreas

Question 13

Stratified Columnar

Answer 13

• Several layers of cells where the superficial cells are elongated and the basal cells are cube shaped
• Found in the male urethra and linings of exocrine glands

Question 14

Transitional

Answer 14

• Specialized layer to change in response to increased tension
  
  • Found in the inner linings of the urinary bladder
    Made of multiple layers of irregular shaped cells and can elongate or stretch when the urinary bladder fills up

Question 15

Glandular Epithelium

Answer 15

• Composed of cells specialized to produce and secrete substances into ducts or into bodily fluids
  Found within cuboidal or columnar tissue and one or more of these cells is called a gland

Question 16

Types of Glands

Answer 16

• Exocrine: glands which secrete products into the ducts that open onto surfaces like the skin or the lining of the digestive tract
• can be either unicellular or multicellular
• Endocrine: glands which secrete products into tissue fluid or blood

Question 17

two types of Duct complexity structures in Glands

Answer 17

• Simple gland: communicates with the surface by means of a duct that does not branch before reaching glandular cells or secretory portions
• Compound gland: has a duct which branches repeatedly before reaching the secretory portion

Question 18

Two Shapes of Glands

Answer 18

• Tubular glands: glands consisting of epithelial lined tubes
• Alveolar glands: glands with terminal portions that form saclike dilations

Question 19

Classification based on method of secretion

Answer 19

• Merocrine: by method of exocytosis secretes products from salivary and sweat glands and the pancreas
  
  • Apocrine: glands that lose small portions of their glandular cell bodies; mammary and ceruminous glands
  • Holocrine: glands that release entire cells which are disintegrated after releasing sebaceous glands

Question 20

Classification based on merocrine cell secretion products

Answer 20

• Serous fluid: watery and slippery which lubricates
• Mucous: a thicker fluid which is rich in the glycoprotein mucin and it lines the inner linings of digestive, respiratory and reproductive systems to protect

Question 21

Connective Tissue and types

Answer 21

• Connective tissue proper
  
  • Specialized connective tissues
    ○ Cartilage, bone and blood
  • Its composed of protein fibers, and a ground susbtance
    It binds, supports and provides a medium through which substances can be transferred

Question 22

Cell types in Connective Tissue: Fibroblasts

Answer 22

most common type of fixed cell which produces fibers by secreting proteins into the extracellular matrix
- Respond rapidly to injuries by increasing in number and fiber production
- E.g. form scar tissue

Question 23

Cell types in COnnective Tissue: Macrophages

Answer 23

white blood cells which attach to fibers usually and are scavenger cells which clear foreign particles from tissue

Question 24

Mast Cells in Connective Tissue

Answer 24

large and widely distributed in connective tissue and are often near blood vessels which release heparin, a compound preventing blood clotting - Also release histamine which stimulates inflammation and

Question 25

Connective Tissue Fiber Types

Answer 25

Collagen: thick threads of protein collagen which are grouped in long parallel bundles which are flexible but only slightly elastic - Have great tensile strength and can resist considerable pulling force Elastic: yellowish springlike protein called elastin which is fibers that branch forming complex networks - Slightly weaker than collagen but are easily stretched but can return to their original lengths and shape when the force acting on it is removed Reticular: thin collagen fibers which are highly branched and form delicate supporting networks

Question 26

Areolar Connective Tissue

Answer 26

forms delicate, thin membranes throughout the body - Fibroblasts are located some distances apart and are separated by a gel like ground substances containing collagen and elastic fibers - Binds tissue to the skin of underlying organs - Lies below layers of epithelium

Question 27

Adipose

Answer 27

adipocyte cells which initially resemble fibroblasts but accumulate fat and enlarge, with their nuclei pushed to the side which when they become abundant, form tissue - Found beneath the skin in spaces between muscles, around kidneys, behind the eyes, in abdominal membranes and around the heart and certain joints - Cushions joints and organs and insulates beneath the skin - Brown fat cells have many mitochondria to generate heat to warm up, white fat stores nutrients for nearby cells to use

Question 28

Reticular Connective Tissue

Answer 28

thin reticular fibers in a 3d network which provides the framework of certain internal organs - Found in liver and spleen

Question 29

Dense Regular Connective Tissue:

Answer 29

many closely packed thick collagen fibers, a fine network of elastic fibers and a few fibroblast cells - Strong and enables tissue to withstand pulling forces, allowing it to bind body structures together - Found in tendons and ligaments - Poor blood supply making tissue repair slow

Question 30

Dense Irregular Connective Tissue

Answer 30

thicker and more interwoven and randomly distributed than dense regular - Irregular placed fibers allow tissue to sustain tension in many different directions - Found in the periosteum, covers bones, and in the dermis(inner skin layer)

Question 31

Elastic Connective Tissue

Answer 31

consists of yellow elastic fibers in parallel strands or in branching networks which collagen fibers and fibroblasts in between - Found in attachments between bones of the spinal column and in the layers within the walls of hollow internal organs like arteries - Imparts an elastic quality

Question 32

Cartilage

Answer 32

rigid connective tissue which has an abundant extracellular matrix largely composed of collagen fibers in a gel like substance with chondrocytes found in lacunae - Enclosed in a covering of connective tissue known as perichondrium - Lacks direct blood supply therefore heals slowly Types of Cartilage Tissue: differentiated by extracellular matrix

Question 33

Hyaline Cartilage

Answer 33

ery fine collagen fibers with a matrix that looks somewhat like white glasss ○ Found on the ends of bones in joints, in the nasal septum ○ Involved in development and growth of bones

Question 34

Elastic Cartilage

Answer 34

more flexible due to it having a dense network of elastic fibers ○ Found in the external ears ○ Provides flexible framework

Question 35

Fibrocartilage

Answer 35

tough tissue with lots of collagen fibers ○ Found between vertebrae ○ Absorb shock, cushions bones in knee and pelvis

Question 36

Bone

Answer 36

most rigid connective tissue which hardens due to calcium phosphate and calcium carbonate between cells and has many collagen fibers which are flexible and reinforce components of bone ○ Protects vital structures and is an attachment for muscles

Question 37

Types of Bone Tissue

Answer 37

- Compact Bone: osteocytes(osteoblasts in lacunae) are concentrically clustered around a central canal and form an osteon, making up the solid part of the outer portion of bone § Central canals contain blood vessels and canaliculi which are cytoplasmic processes allowing rapid movement of materials between bone cells and blood vessels - Spongy Bone: forms the interior portion of a bone in which bone matrix is deposited around osteocytes, forming bony plates with space in between which lighten the weight of the bone and provide space for bone marrow

Question 38

Blood Tissue

Answer 38

composed of red blood cells, white blood cells and platelets suspended in plasma - Transports gases, fights infection, aids in blood clotting

Question 39

Epithelial Membranes

Answer 39

thin structures that are composed of epithelium and underlying connective tissue - Involved in covering body surfaces and lining body cavities - serous - mucous - cutaneous - synovial

Question 40

Serous membranes

Answer 40

line body cavities that don’t open up to the outside and reduce friction between organs and cavity walls - Composed of a layer of simple squamous epithelium and a thin layer of areolar connective tissue - The cells secrete watery serous fluid to help lubricate

Question 41

Mucous membranes

Answer 41

line the cavities and tubes that open to the outside of the body including oral, nasal cavities, tubes of the digestive, respiratory, urinary and reproductive systems - Consists of epithelium, varying on the location, overlaying a layer of areola connective tissue - Goblet cells secrete mucus

Question 42

Cutaneous membranes and Synovial Membranes

Answer 42

- Cutaneous: part of the integumentary system - Synovial membrane: composed entirely of connective tissue and is found lining joints

Question 43

Skeletal Muscle Tissue

Answer 43

forms muscles that attach to bones and can be voluntary contracted to produce movement - Have long muscle fibers that are multinucleate and have striations - Stimulated by nerve cells

Question 44

Smooth Muscle Tissue

Answer 44

non striated muscle cells which are shorter and spindle shaped with a single, central nucleus and are involved in involuntary contractions of internal organs - Lines the walls of internal organs such as the stomach, esophagus, intestines, urinary bladder, uterus and blood vessels

Question 45

Cardiac Muscle Tissue

Answer 45

found only in the heart and has branched, striated cells that are joined in interconnected complex networks which is involved in involuntary contractions of the heart - Single nucleated cells

Question 46

Nervous Tissue

Answer 46

found in the brain and spinal cord and is responsible for transmitting neuron impulses to other cells to help coordinate and regulate body functions - Neurons have processes which receive and transmit stimuli - Shorter and branched is dendrites, single long is the axon - Also loads of neuroglia which support and bind the components of the nervous tissue, carry on phagocytosis and supply growth factors to neurons