Cells And Tissues, The Skin

Question 1

What is the epithelium?

Answer 1

The lining, covering, and glandular tissue of the body

Epithelial cells form continuous sheets and have specialized functions.

Question 2

What are the characteristics of epithelial cells?

Answer 2

Fit closely together, form continuous sheets, bound by cell junctions, have an apical surface, and rest on a basement membrane

Includes desmosomes and tight junctions.

Question 3

What is ‘morphological polarity’ in epithelium?

Answer 3

The presence of an apical surface exposed to the body’s exterior or internal cavities

Some epithelia may have microvilli or cilia.

Question 4

What is the vascularity of epithelial tissues?

Answer 4

Avascular; they depend on diffusion from underlying connective tissue for nourishment

They regenerate easily when well-nourished.

Question 5

List the functions of epithelial tissue.

Answer 5

• Protection
• Absorption
• Filtration
• Secretion
• Receptors for special senses

Examples include skin, stomach lining, kidney tubules, and glands.

Question 6

What are the classifications of epithelium based on cell layers?

Answer 6

• Simple (one layer)
• Stratified (multiple layers)
• Pseudostratified (one layer with varying cell shapes)

Stratified epithelium varies in thickness and function.

Question 7

What are the shapes of epithelial cells?

Answer 7

• Squamous (flattened)
• Cuboidal (cube-shaped)
• Columnar (tall)

These shapes influence the functions of the epithelium.

Question 8

What is the function of simple squamous epithelium?

Answer 8

Passage of materials by diffusion and filtration where protection is not important

Also secretes lubricating substances in serous membranes.

Question 9

What characterizes simple cuboidal epithelium?

Answer 9

Single layer of cube-like cells with large, spherical nuclei; functions in secretion and absorption

Found in renal tubules.

Question 10

Describe the function of simple columnar epithelium.

Answer 10

Absorption and secretion; may contain cilia and goblet cells

Commonly found in the small intestine.

Question 11

What is pseudostratified columnar epithelium?

Answer 11

Single layer of cells of differing heights that gives a false appearance of multiple layers; functions in secretion and propulsion of mucus

Found in the trachea.

Question 12

What is the function of stratified squamous epithelium?

Answer 12

Protecting underlying tissues in areas subjected to abrasion

Commonly found in the skin.

Question 13

What is transitional epithelium specialized for?

Answer 13

Protection and stretching to accommodate distension of urinary structures

Found in the urinary bladder.

Question 14

What distinguishes glandular epithelium from covering epithelium?

Answer 14

Glandular epithelium forms various glands and secretes products

Covering epithelium covers body surfaces.

Question 15

What are exocrine glands?

Answer 15

Glands that secrete products via ducts that open onto body surfaces

Examples include sweat and oil glands.

Question 16

What are endocrine glands?

Answer 16

Ductless glands that secrete hormones directly into the blood

Examples include the thyroid and adrenal glands.

Question 17

Define autocrine signaling.

Answer 17

A cell targets itself

Important in cellular communication.

Question 18

What is paracrine signaling?

Answer 18

A cell targets a nearby cell

Plays a role in local signaling.

Question 19

What is the function of ground substance in connective tissue?

Answer 19

Fills space between cells, allows cell attachment, and serves as a medium for nutrient diffusion

Acts as a connective tissue glue.

Question 20

What are the types of connective tissue fibers?

Answer 20

• Collagen (high tensile strength)
• Elastic (stretch and recoil)
• Reticular (support soft tissue)

Fibers provide structural support.

Question 21

What are the two forms of connective tissue cells?

Answer 21

• Immature (blast)
• Mature (cyte)

Immature cells secrete ground substance and fibers.

Question 22

What characterizes loose connective tissue?

Answer 22

Contains areolar, adipose, and reticular tissues

Functions include cushioning and support.

Question 23

What is the function of dense regular connective tissue?

Answer 23

Attaches muscles to muscles or to bones; withstands tensile stress

Found in tendons and ligaments.

Question 24

What is the primary cell type in cartilage?

Answer 24

Chondroblasts produce new matrix until growth stops; mature cells are chondrocytes

Cartilage is avascular and lacks nerve fibers.

Question 25

What distinguishes hyaline cartilage?

Answer 25

Most abundant type, contains a lot of collagen, appears glassy ## Footnote Found at the ends of bones as articular cartilage.

Question 26

What is the function of fibrocartilage?

Answer 26

Absorbs compressive shock and provides tensile strength ## Footnote Found where hyaline cartilage meets ligaments or tendons.

Question 27

Differentiate between skeletal, cardiac, and smooth muscle.

Answer 27

* Skeletal: voluntary, striated, multi-nucleated * Cardiac: involuntary, striated, branched * Smooth: involuntary, non-striated, spindle-shaped ## Footnote Each type has distinct locations and functions.

Question 28

What is the sarcomere?

Answer 28

The contractile unit of muscle that induces shortening ## Footnote Composed of actin and myosin filaments.

Question 29

What are the layers of the skin?

Answer 29

* Epidermis * Dermis * Subcutaneous tissue/hypodermis ## Footnote Each layer has distinct structures and functions.

Question 30

What is the primary function of the stratum corneum?

Answer 30

Provides a barrier to prevent water loss ## Footnote Composed of dead, keratin-filled cells.

Question 31

What is the function of the dermis?

Answer 31

Binds the body together, contains phagocytes, and has a rich nerve supply ## Footnote Provides structural strength and elasticity.

Question 32

What are dermal papillae?

Answer 32

Peg-like projections in the papillary layer that indent the epidermis ## Footnote Contain capillary loops supplying nutrients to the epidermis.

Question 33

What helps to bind the body together?

Answer 33

Dermis ## Footnote The dermis contains phagocytes and is very vascular, playing a role in thermoregulation.

Question 34

What is the upper dermal region of the dermis called?

Answer 34

Papillary layer ## Footnote The papillary layer has peg-like projections called dermal papillae.

Question 35

What do dermal papillae contain?

Answer 35

Capillary loops, pain receptors, touch receptors ## Footnote They supply nutrients to the epidermis.

Question 36

What produces the looped and whorled ridges on the epidermal surface?

Answer 36

Papillary patterns on the palms and soles ## Footnote These patterns are formed by dermal papillae.

Question 37

What is the deepest skin layer called?

Answer 37

Reticular layer ## Footnote The reticular layer contains irregularly arranged connective tissue fibers.

Question 38

Which glands are classified as cutaneous glands?

Answer 38

Sebaceous glands, sweat glands, hair follicles, nails ## Footnote Cutaneous glands are exocrine glands that release secretions to the skin surface.

Question 39

Where are sebaceous glands found?

Answer 39

All over the skin except on the palms and soles ## Footnote Their ducts can empty into a hair follicle or onto the skin surface.

Question 40

What do sebaceous glands produce?

Answer 40

Sebum ## Footnote Sebum is an oily substance that acts as a lubricant and contains antibacterial chemicals.

Question 41

What are the two types of sweat glands?

Answer 41

Eccrine sweat glands, apocrine sweat glands ## Footnote Both types are involved in temperature regulation and have different functions.

Question 42

Where are eccrine sweat glands most abundant?

Answer 42

All over the body ## Footnote They produce sweat that is important for temperature regulation.

Question 43

What is the role of apocrine sweat glands?

Answer 43

Function during puberty and found in axillary and genital areas ## Footnote They are larger than eccrine glands and empty into hair follicles.

Question 44

What is the hair part enclosed in the follicle called?

Answer 44

Root ## Footnote The part projecting from the surface is called the shaft.

Question 45

What happens to the daughter cells of hair follicles as they are pushed away from the growing region?

Answer 45

They become keratinized and die ## Footnote The bulk of the hair shaft is made up of dead cells.

Question 46

What are the protective functions of hair?

Answer 46

Guarding against bumps, shielding eyes, keeping foreign particles out ## Footnote Hair provides minor protective functions.

Question 47

What are the main functions of the skin?

Answer 47

Protection, temperature regulation, cutaneous sensation, metabolic functions, blood reservoir, excretion ## Footnote These functions are essential for maintaining homeostasis.

Question 48

Fill in the blank: The top surface of skin is _______ and waterproof.

Answer 48

avascular ## Footnote This characteristic helps prevent water loss.

Question 49

True or False: Apocrine sweat glands are important for thermoregulation.

Answer 49

False ## Footnote Eccrine glands are primarily responsible for thermoregulation.