Integumentary System

Question 1

Functions of Skin?

Answer 1

1. Provides a waterproof barrier
2. Sensory receptors
3. Regulates body temperature
4. Aids in vitamin D production
5. Excretion and absorption

Question 2

Skin’s two major components?

Answer 2

1. Cutaneous membranes (epidermis and dermis)

2. Accessory structures (nails, hair, glands)

Question 3

Cutaneous membrane’s principal layers?

Answer 3

Epidermis: the outer layer of skin, made up of stratified squamous epithelium, keratinocytes, melanocytes, Langerhans cells, Merkel cells

Dermis: deep layer of skin, made up of areolar connective tissue (in the papillary region) and dense irregular connective tissue (in the reticular region) containing collagen fibers

Hypodermis/subcutaneous layer: fat

Question 4

Name the 5 layers of the epidermis from superficial to deep

Answer 4

1. Stratum Corneum (25-30 layers of flattened dead keratinocytes)
2. Stratum Lucidum (4-6 layers of flattened clear dead keratinocytes. Only in thick skin)
3. Stratum Granulosum (3-5 layers of keratinocytes going through apoptosis/ cell death)
4. Stratum Spinosum (Many keratinocytes in 8-10 layers, appears rounded)
5. Stratum Basale (single layer of cuboidal or columnar keratinocytes)

Question 5

Name the 2 regions of the dermis

Answer 5

Papillary Region: consists of areolar connective tissue, dermal papillae, and capillary loops

Reticular Layer: consists of dense irregular connective tissue (for strength and elasticity), and some adipose tissue, nerves, and glands

Question 6

Name the accessory structures of the skin

Answer 6

Hair shaft, hair root, arrector pili muscle, glands (sebaceous, eccrine, apocrine), hair root plexus, hair bulb, papilla of the hair, blood vessels

Question 7

What are Sudoriferous Glands and what are the two types?

Answer 7

Sudoriferous glands: glands that release sweat or perspiration into hair follicles or onto the skin’s surface through pores.

2 Types: Eccrine (merocrine) glands, Apocrine glands

Question 8

What are Sebaceous Glands?

Answer 8

Oil producing glands connected to hair follicles.

Location: the secreting portion lies in the dermis and usually opens into the neck of a hair follicle

Functions: secrete sebum. keep hair from drying/ brittleness, prevent excessive evaporation, inhibit growth of some bacteria

Question 9

Function of Eccrine Sweat Glands?

Answer 9

Helps regulate body temperature through evaporation

Location: secreting portion is in deep dermis, excretory duct projects through the dermis and epidermis and ends as a pore at the surface of the epidermis

Most dense in forehead, palms, and soles

Question 10

Function of Apocrine Sweat Glands?

Answer 10

Secrete pheromones (body odor) from emotional sweat or sexual activity. Sweat appears milky/ yellow

Location: secretory portion is in the lower dermis of the upper subcutaneous layer and the excretory duct opens into hair follicles

Found densely in the skin of axilla, groin, areolae, and bearded regions in adult male

Question 11

What are the 4 primary tissue types?

Answer 11

Connective, Muscle, Epithelial, Nervous

Question 12

Describe muscle tissue

Answer 12

Function: body movement, maintain posture, generate heat, protect internal organs

Consists of fibers, (myocytes) which are elongated muscle cells that shorten to cause movement

Question 13

What are the 3 types of muscle tissue?

Answer 13

Skeletal, Cardiac, and Smooth

Question 14

Describe skeletal muscle

Answer 14

Location: attached to bones and skin

Function: moves bones and skin, generates heat

Appearance: striations (light/dark), muscle fibers, nuclei (myocyte), and capillaries

Question 15

Describe cardiac muscle

Answer 15

Location: wall of the heart

Function: movement of blood throughout the cardiovascular system

Appearance: striations, intercalated disks, nuclei, branching fibers

Question 16

Describe smooth muscle

Answer 16

Location: walls of arteries and veins, walls of bladder and urethra, intrinsic eye muscle

Function: controls blood flow and blood pressure, movement of urine through urinary tract, control pupil size

Appearance: spindle-shaped fibers, 1 nucleus per cell

Question 17

Describe nervous tissue

Answer 17

Nervous tissue forms the brain, spinal cord, and nerves

Has two categories:
1. Neurons (receive and send information, has one or more processes, consists of dendrites and one axon)
2. Neuroglia (supports the neurons and helps them to function)
There are lots of neuroglia in one neuron cell

Question 18

Describe connective tissue

Answer 18

Most abundant primary tissue in the body.
Extracellular matrix: fibers and ground substance synthesized/secreted by connective tissue cells
Ground substance: fluid, semi-fluid, gelatinous, or hard substance that CT cells secrete into the ECM

Function: depends on the properties of the ECM components

5 Categories: Loose, dense, cartilage, bone, blood

Question 19

Describe areolar connective tissue (loose CT)

Answer 19

Contains fibroblasts, all 3 fiber types (collagen, elastic, reticular), semi-fluid ground substance, and many cells involved in bodily defenses

Location: Beneath all epithelial tissues, subcutaneous layer, and papillary layer

Function: strength, elasticity, support, nutrient diffusion

Appearance: Clearly can see collagen, elastic, and reticular fibers, a few mast cells and granules

Question 20

Describe adipose connective tissue (loose CT)

Answer 20

Contains adipocytes derived from fibroblasts, has very little ECM

Location: subcutaneous layer of skin, around heart and kidneys, yellow bone marrow, padding around joints, behind eyeball

Function: stores lipid for fuel, thermal insulation, cushions organs and joints and endocrine.

Appearance: White circles with pink borders, nuclei around the borders

Question 21

Describe dense regular connective tissue (dense CT)

Answer 21

Little ground substance and few fibroblasts.

Location: ligaments, tendons, aponeuroses

Function: Strong attachment between various structures, withstands tension along long axis of fibers

Appearance: Extracellular matrix is filled with parallel bundles of collagen fibers. Looks like compact ocean waves

Question 22

Describe dense irregular connective tissue (dense CT)

Answer 22

Made up of collagen fibers, usually irregularly arranged with few fibroblasts and little ground substance

Location: reticular region of dermis, fibrous pericardium, periosteum of bone, perichondrium of cartilage, joint capsules, membrane capsules around various organs (kidney, liver, testes, lymph nodes), heart valves

Function: resist pulling forces in MULTIPLE directions

Appearance: Looks like marbled meat

Question 23

Describe hyaline cartilage connective tissue (cartilage CT)

Answer 23

Most abundant cartilage in the body. Ground substance is a resilient gel, also contains fine collagen fibers, and chondrocytes inside lacunae

Location: ends of long bones, anterior ends of ribs, nose, parts of larynx, trachea, bronchi, embryonic, and fetal skeleton

Function: provides smooth surfaces for joint movement, flexibility, and support

Appearance: looks like a sponge due to the lacunae

Question 24

Describe fibrocartilage connective tissue (cartilage CT)

Answer 24

Less abundant cartilage than hyaline. Strongest cartilage. Contains fewer lacunae and chondrocytes. ECM is packed with thick collagen fibers to give tension strength.

Location: pubic symphysis, intervertebral discs, menisci of knee, portions of tendons that insert into cartilage

Function: support and joining structures together, strength and rigidity (strongest type of cartilage)

Appearance: