Chapter 5 Reading Guide
Overview
This reading guide is intended to be used with the Open Stax Anatomy and Physiology textbook.
Open Stax Anatomy and Physiology Chapter 5 Reading Guide
5.1 layers of the skin
- The skin and its accessory structures make up the ___________________________.
- The integumentary system provides the body with overall protection.
- The Epidermis
- The ________________ is composed of keratinized, stratified squamous epithelium.
- Avascular - _____________________________
- Composed of four layers (thin skin) most skin is thin skin.
- Stratum __________ – most deep layer
- Stratum __________ – superficial to basale
- Stratum __________ – superficial to spinosum
- Stratum __________ – most superficial layer
- “Thick skin,” has a fifth layer, stratum __________, which is only found on the palms of the hands the soles of the feet.
- Located between the corneum and granulosum layers.
- ______________, the cells found in all the layers except for the basale layer.
- These cells manufacture and store __________.
- A protein that gives hair, nails, and skin their hardness and waterproofing properties.
- Keratinocytes are dead in the stratum corneum, and regularly shed away and replaced by cells from the deeper layers.
___________________________
- The deepest epidermal layer
- Attaches the epidermis to the basal lamina, below which are the layers of the dermis.
- The basement membrane binds the stratum basale to the underlying dermis.
- _______________________
- Fingerlike projections or folds found in the superficial portion of the dermis.
- Increase the strength of connection between the epidermis and dermis.
- Result in your fingers as fingerprints
- Consists of a single cell layer composed of __________ cells.
- Stem cells that are precursors to keratinocytes
- Other cell types associated with the basale layer
- __________ cells, function as sensory receptors, perceive touch
- __________ which produce the pigment __________.
Stratum __________
- Characteristics
- Spiny appearance in microscope due to __________.
- Consists of eight to ten layers of keratinocytes and dendritic cells called __________cells.
- Langerhans cells function as macrophages, eat bacteria, engulf foreign particles and damaged cells.
Stratum __________
- Characteristics
- Consists of three to five layers of keratinocytes
- Cells flatten, thicker cell membranes, generate large quantities of the protein's keratin and __________
- Cellular organelles disintegrate leaving behind cell membranes and proteins.
Stratum __________
- Characteristics
- Found only in thick skin (soles of feet, and palms of hands)
- Smooth, translucent layer found above the granulosum layer and below the corneum layer.
- Dead, flattened cells that contain the protein __________, which is derived from keratohyalin.
Stratum __________
- Most superficial epidermal layer, consisting of 15 to 30 layers of cells.
- Functions
- Protection from microbe penetration, and dehydration.
- Provides mechanical protection from abrasions.
- Cells are repeatedly shed and replaced by cells from deeper layers
__________
- Characteristics
- Deep to the epidermis
- Contains blood vessels, nerves, sweat glands, and hair follicles.
- Made of two layers of connective tissues which form an interconnected mesh of elastin and collagen produced by fibroblasts
Layers of the Dermis
__________ layer:
- Loose, areolar connective tissue, forms finger-like dermal papillae that project into the stratum basale
- Contain fibroblasts, adipocytes, phagocytes, and blood vessels.
- Also contains lymphatic capillaries, nerve fibers, and Meissner corpuscles (touch receptors).
__________ layer
- Deep to the papillary layer
- Dense, irregular connective tissue
- Well vascularized, rich nerve supply
- Elastin fibers for a tight meshwork which provides elasticity.
- Collagen fibers provide structure and tensile strength
_______dermis
- Also known as the subcutaneous layer or superficial fascia.
- Connects the skin to the underlying fascia of the muscles and bones.
- It is composed of areolar and adipose tissues
- Functions in fat storage, insulation, and cushioning of the integument
Pigmentation
- Skin color is influence by the presence of melanin, carotene, and hemoglobin
- Melanin Production:
- Melanin is produced by melanocytes in the stratum basale.
- Melanin is transferred to other keratinocytes by cellular vesicles called _____________.
- Melanin occurs in two forms
- __________ is black and brown
- _____________ is a red color
- Darker-skinned individuals produce more melanin than lighter-skinned individuals.
- Exposure to UV rays causes melanin to be produced.
- Increased melanin production protects the DNA in epidermal cells from UV damage and breakdown of folic acid.
- Can interfere with the production of Vitamin D.
5.2 Accessory Structures of the Skin
Hair
- A keratinized filament that originate from __________follicles.
- Hair ________ – the part of the hair that grows out of the hair follicle.
- Hair ______ – the part of the hair attached to the hair follicle.
- Hair ________ – is where the root ends in the dermis which contains a layer of mitotically active cells called the hair matrix.
- Hair ________ – surrounded by the hair bulb which is made of connective tissue and contains nerve endings and blood capillaries.
Hair
Hair follicles originate in the epidermis and have many different parts.
Process of Hair Formation
- The basal cells of the hair bulb divide push cells outward in the hair root and shaft.
- _________ forms the central core of the hair shaft, surrounded by the __________, and an outer layer called the __________.
- Hair texture (straight, curly) is determined by the shape and structure of the cortex
- The external hair (visible to you) is dead cells composed entirely of keratin.
- Hair follicle structure:
- Three concentric cell layers
- __________ root sheath a layer of cells that surround the root of the growing hair
- External root ________ is a cell layer that encloses the hair root.
- Glassy _________ – connective tissue sheath Functions of Hair
- Protection, sensory input, thermoregulation, and communication.
- Each hair root is connected to a smooth muscle called the _________ pili.
- Goose bumps or hair standing on end.
Hair Growth
- Occurs in three phases
- ________ – cells divide rapidly at the root, push the hair shaft up and out.
- __________ – transition from active growth to no growth.
- __________ – hair follicle at rest with no active growth
Hair Color
- Is due to the pigment melanin produced by melanocytes in the hair papilla.
Nails
- Found at the tips of fingers and toes.
- Structure of nails
- Nail _______ forms on the ________ bed.
- Protects the tips of fingers and toes.
- Nail _______ forms the nail body.
- Nail ________– overlaps the nail on the sides to anchor the nail body
- Nail cuticle (_______________) the proximal end of the nail body
- _________ – a thickened layer of epithelium over the nail matrix.
- _____________ – the area below the free edge of the nail.
Sweat Glands
- _____________ glands produce sweat to cool the body
- __________ glands produce secretions by exocytosis through a duct
- _________ sweat gland – produce a hypotonic sweat for thermoregulation.
- This sweat is mostly water with dissolved salts, antibodies, metabolic wastes and dermicidin (antimicrobial peptide).
- __________ sweat gland is associated with hair follicles in the armpits and genital regions
- Produce a thicker, sweat that is subject to bacterial decomposition and smell.
- Sebaceous Glands
- Oil glands to help lubricate and waterproof the skin and hair.
- Excrete __________ a mixture of lipids.
- Activated by puberty hormones
5.3 functions of the integumentary system
__________
- Protection from wind, water and UV sunlight.
- Protection from dehydration
- Protection from abrasion, microbes, and chemicals
__________ Function
- Sense organ because the epidermis, dermis and hypodermis contain sensory receptors.
- __________ (tactile) corpuscle responds to light touch
- __________ (lamellated) corpuscle respond to vibrations
- __________ cells mentioned earlier
- Sensory nerves connected to each hair follicle
- Pain and temperature receptors scattered throughout the skin.
- Motor nerves innervate the arrector pili and glands in the skin.
Thermoregulation
- Through association with the __________ nervous system (SNS) (flight or f______ responses).
- The SNS monitors body temperature and executes an appropriate motor response (i.e. sweating).
- Arterioles in the dermis dilate so that excess heat dissipates through the skin into the surrounding environment.
- The same arterioles will constrict to minimize heat loss when it is cold.
Vitamin D Synthesis
- Occurs in the epidermal layer
- In the presence of sunlight:
- Vitamin D3 (cholecalciferol – a derivative of cholesterol) is synthesized.
- In the liver cholecalciferol is converted to calcidiol, which in the kidneys is converted to calcitriol (the active form of _____________).
- Vitamin D is essential for the normal absorption of calcium and phosphorus for health bones.
- Absence of sunlight and vitamin D leads to __________ in children.
- In elderly individual's vitamin D deficiency causes __________ which is a softening of the bone.
- Vitamin D is needed for general immunity and lack of it may predispose one to cancer.
5.4: Diseases, disorders, and injuries of the integumentary system
- Skin cancer is one of the most talked about diseases in human beings.
- Cancer is a disease characterized by abnormal cells dividing uncontrollably.
- One out of five Americans will experience some type of skin cancer
- Chief cause is overexposure to UV radiation.
- Many tumors are benign (harmless)
- But some produce cells that can mobilize and move into other body parts and start growing there (__________)
- Cancers are characterized by their ability to metastasize.
Basal Cell Carcinoma
- ______________carcinoma affects the stem cells in the stratum basale.
- Most common form of all cancers that occur in the United States.
- Caused by overexposure to UV rays, and other forms of radiation along with arsenic.
- Open sores, tattoos, burns, may be predisposing factors
- Start in the stratum basale and spread out from there.
- Respond very well to early treatment
Squamous cell carcinoma
- _____________ cell carcinoma affects the cells of the stratum spinosum.
- Most commonly presents as lesions on the scalp, ears, and hands.
- Second most common form of skin cancer.
- More aggressive than basal cell carcinoma, can metastasize if not removed early.
Melanoma
- _____________ is a cancer caused by uncontrollable growth of melanocytes, typically develop from a mole
- The most fatal of all skin cancers, highly metastatic and can spread easily before detection.
- Usually appear as asymmetrical brown and black patches
- The ABC’s of early diagnosis of melanoma
- When observing moles displaying the following signs it is wise to consult a doctor immediately
- A__________ – the two sides are not symmetrical
- B__________ – the edges are irregular in shape.
- C__________ – the color is varied shades of brown and black.
- D__________ – it is larger than 6 mm (0.24 in).
- E__________ – its shape has changed.
- Additional signs to look for as suggested by specialists for nodular melanoma (most serious form).
- E__________ – it is raised on the skin surface
- F__________ – it feels hard to the touch.
- G__________ – it is getting larger.
Skin Disorders
- Two common disorders are eczema and acne
- __________ an inflammatory condition that results from an allergic reaction
- Manifests itself as swelling of the skin, flaking, rashes, and bleeding
- Most suffers have antibodies against dust mites in their blood.
- __________ involves clogging of pores which can lead to infection, and inflammation.
- Most common in adolescents
- Occurs in areas rich in sebaceous glands (face and back).
- Most common during puberty
- Androgens stimulate the release of sebum, an overproduction and accumulation can block hair follicles
- The infection is caused by acne – causing bacteria.
Injuries
- Burns
- Burns result from intense heat, radiation, electricity, or chemicals.
- Damage results in the death of skin cells which leads to loss of fluids
- Burn Classifications
- (rule of nines) determines the total surface area of the body affected,
- Degree of severity
- _________-degree burn – is superficial and only affects the epidermis. Reddening of the skin and some swelling
- __________-degree burn – is deeper, affects the epidermis and upper dermis. Result in swelling and blisters.
- __________-degree burns - results in destruction of the epidermis and dermis, much more serious, require medical attention.
- __________-degree burns – Most severe affects underlying muscle and bone.
Scars and Keloids
- Scar is collagen-rich skin formed due to repair of skin damage but no regeneration of the original skin structure.
- Keloid is the result of collagen formation that continues after the wound is healed. This results in the formation of a raised scar.
Bedsores and Stretch Marks
- A bedsore (__________ ulcer) results from long-term, unrelieved pressure on body parts that are bony, reducing blood flow, and leading to necrosis.
- A stretch mark is caused by pressure associated with rapid growth. They result when the dermis is stretched beyond its limits of elasticity
Calluses
- Calluses form on parts of the body that are subjected to constant sources of abrasion.
- This results in thickening of the skin at the abrasion point to protect the rest of the body from further damage.
- Corns – specialized callus, form on your feet and toes.