Name Unit 4: Cell communication 1. Describe the ways Cells ...
3J: Analyze the life cycle of cells in the body and describe the effects of aging of cells and...
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Transcript of 3J: Analyze the life cycle of cells in the body and describe the effects of aging of cells and...
Learning Goals:
3J: Analyze the life cycle of cells in the body and describe the effects of aging of cells and tissues
3K: Evaluate possible causes of cancer and describe the process of cancer growth
Learning Goals:
Turn to page 95 in textbook
Write down each objective on green learning goal paper. Each objective gets its own box.
Body Membranes
Cover surfaces & line cavitiesForm protective & lubricating sheet around organs
2 categories:1. epithelial2. connective
Epithelial Membranes
Named inaccurately – actually a simple organ because is made of epithelial & connective tissues
3 types:1. mucous2. serous3. cutaneous
Mucous Membranes
Description:- Considered a “wet” or moist membrane - continuous secretions
Locations: all body cavities that open to the outside of body
Functions: absorption and/or secretion
Serous membranes
Line body cavities that are closed to the outside
Function :protective barrier over organs allows movement without friction-
SEROUS FLUID - allows organs to slide w/o friction
Cutaneous Membrane
Skin
Function - protection & temperature control
Includes hair, nails, sweat & oil glands, sensory receptors
a “dry” membrane exposed to air
Synovial Membranes
Locations: 1. surrounds joints2. surrounds bursae
(small sacs of tissue)3. surrounds tendons
Functions:1. provide a smooth surface2. secrete lubricating fluid3. cushion organs during
movement
LG 4c: 8 Functions of
1. Forms body covering2. Waterproof barrier3. Insulates & cushions deeper organs4. Protective barrier against:
- mechanical, chemical, thermal, UV, bacteria
5. Regulates heat loss6. Secretes sweat & oil7. Makes proteins & vitamin D8. Provides sensory information
- touch, pressure, temp., pain
LG 4D: Integumentary System
Made of: 1. skin2. sweat &
oil glands3. hair4. nails5. sensory
receptors
Structures of Skin
Composed of 2 layers1. Epidermis – outermost layer
- made of stratified squamous - ability to keratinize – become
hard & tough2. Dermis – underlying the epidermis
- made of connective tissue
***Both are tightly connected together***However, a burn or friction can
separate them resulting in a blister.
Melanin- protein found the epidermis- made by cells called melanocytes- same amount of these cells in all people- darker skin = more active- lighter skin = less active- natural sunscreen (protects from UV rays
Keratin - protein made in the epidermis
- made from cells called keratinocytes
- makes our skin waterproof- the main component of hair & nails
Layers of the Dermis
Varies in thickness –
depends on location-palms & soles: thick - eyelids: very thin
2 layers:- papillary- reticular
Papillary Layer
upper layer Includes:- free nerve endings – pain- Meissner’s corpuscles –
touch Fingerprints – whorls &
ridges- fingers & feet-increase friction & gripping-formed in the womb- all are unique….
Even in identical twins!
Reticular Layer Deepest skin layer Contains:
- blood vessels, sweat & oil glands- Pacinian corpuscles – deep pressure
- phagocytes –destroy bacteria Made of
- collagen – keeps skin hydrated- elastin – gives skin elasticity - with age, it decrease and
creates wrinkles & begins to sag.
Cutaneous Glands
Sebaceous Glands (oil glands)- found everywhere, except palm &
soles- excrete SEBUM into the follicle or
surface of skin- SEBUM – keeps skin soft & moist &
prevents hair from becoming brittle
- contains chemicals to kill bacteriaDuring puberty – becomes very active..
Leads to oily skin & increase acne.
Sudoriferous Glands (Sweat)
Eccrine – most numbrous, found all over body- produce sweat – clear fluid, primarly water
& salts, wastes & lactic acid.- released through pores- critical in temperature regulation of
bodyAprocrine – axillary & genital areas only
- excrete into hair follicles- produce sweat that is yellow & can be
cloudy- odorless until bacteria living on skin uses it
as food, then it becomes stinky!!
Subcutaneous Layer (Hypodermis)
Composed of adipose tissue Not considered part of skin Anchors the skin to underlying organsFunctions:
1. shock absorber2. insulates from extreme
temperature changes outside the body
3. responsible for the differences between the man & woman body structure.
Hair
Millions of hairs are scattered all over the body, except palms, soles, nipples, & lips
Functions:- guarding the head from UV rays and bumps- shielding the eyes- helps keep particles out of respiratory tract
Hair has lost much of its usefulness…. Hair for Early humans provided insulation
in cold weather. Now we have clothes
Hair ….. continued
Flexible epithelial structure Dead, keratinized cells Different colors – made by varying
amounts of melanin. Variety of sizes and shapes:
- eyebrows: short & stiff- hair of head: long & flexible
Shape of hair shaft determines what texture your hair will be… oval = smooth & silky; flat= curly; round = straight & coarse
Hair…. conclusion
Humans are born with as many hair follicles as they will ever have
Among the fastest growing tissues in the body
Hormones control hair growth By age 50, number of hair follicle drop
to 1/3 and continue to decline. Results in hair thinning and different
degrees of baldness Gray hair – results from the absence of
melanin