Cell Organelles carry out specific jobs in the cells, like making certain molecules or digesting waste materials
Cells Are the basic unit of life that is capable of carrying out all the functions of living things independently Work together to form tissues Metabolism Homeostasis Ability to reproduce/Genetic material Growth and Development Response to stimuli
Homeostasis The body must maintain conditions within certain parameters This means control over things like: temperature pH blood gases (oxygen, carbon dioxide)
Homeostatic mechanisms operate to maintain the body within tolerable limits by using: a. Sensory receptor cells detect specific changes in the environment. b. Integrators act to direct impulses to the place where a response can be made. c. Effectors perform the appropriate response. 5 senses, temperature sensors, etc Brain and spinal cord Muscles and glands
Everything has a role to play in homeostasis The combined contribution of cells and the tissues they form, and the organs and systems formed from these all work to maintain a stable internal environment for a living being
What do the pieces of the body do to help? Cells are bathed in fluid: 4 Gallons of extra-cellular fluid (between cells- called interstitial fluid) Each cell carries out metabolic activities to ensure the survival of the cell Cells of each tissue act together to perform one or more duties that contribute to the survival of an organism as a whole by forming organs that work together in a system
Feedback Mechanisms (2 types) Positive Causes the situation to intensify Cough up germs, produce more mucus, cough more, irritate throat, cough more, more mucus… Sexual response Oxytocin production in labor causes uterine cramping, which causes production of oxytocin which causes cramping which causes more oxytocin production….
Negative feedback Causes the situation to stop/ reverse conditions Like a thermostat turns off the heat when it gets to a preset temperature Usually things are just turned on or off; you produce insulin (or other hormone) and when you have enough, production stops; when you need more, you produce more
Skin description: Use the vocabulary from the image to write a description of skin
Skin: The Integumentary System from the Latin integere- to cover Demonstrates all of the tissues working together to keep on organism alive The average person has 9 pounds of skin The skin is about 15-20 square feet
Functions of the skin: prevents dehydration Prevents microbial invasion/ infection Prevents abrasion Stores blood Provides cushioning Insulation (temp, physical) Receives stimuli (touch, temp, pressure) Temperature regulation Produces vitamin D Pheromone secretion Excrete salt waste (small counts)
The Epidermis Has no nerves Dead layers of flat epithelial cells; the very top is called the stratum corneum Contains keratin: a tough protein that waterproofs the skin Quite a bit gets rubbed off each day (dust) Skin color is due to –melanocytes (pigmented cells- genetics and sun exposure play roles) –blood flow –carotene
Layers of the Epidermis Stratum corneum Stratum lucidum Stratum granuosum Stratum spinosum Stratum basale (basal cell layer)
The Dermis of the skin Made from mostly connective tissue –Irregular and dense CTs Role is mainly to protect underlying tissues Contains: –Blood vessels –Lymph vessels –Nerve endings –Sweat glands –Oil glands –Hair –Nails
More on the dermis and sweat glands… Sweat (sudoriferous) glands are present to control temperature, but respond to –Stress (frightened, upset, etc) –pain, and –sexual stimuli
Types of Sweat Glands –Two types: Eccrine glands (mostly temperature regulation sweat) –Foredead, neck, back, »palms and soles from stress Apocrine glands (scented sweat glands; sweat is broken doen by bacteria, producing a scent) –Found in the axillary and inguinal areas
More on the dermis and sweat glands… Sweat is made up of –water, –salts, –ammonia, –vitamin C, –other wastes and –(possibly) pheromones
Pheromones Are chemicals secreted by the body that other animals of the same species respond to (communication molecules) –Usually associated with reproduction, but not always Are well documented in animals –Syrian golden hampsters (dimethyl disulfide to attract, aphrodisin to copulate) –Cockroaches (periplanone B) –Ethiopian civet cat and Himalayan musk deer (musk) –Pigs (androstenone) Usually have no smell associated with them Secreted in very small amounts Some evidence for pheromone presence in humans –VNO (vomeronasal organ) in people; used to detect pheromones in animals
Oil glands…. Otherwise known as sebacious glands Lubricate hair and skin by producing sebum (fatty substance that includes lipids and cellular debris made in holocrine glands) Oil kills microbes (bacteria) None present on soles of feet or the palms of the hands (but they are present on the fingertips)
We leave prints behind… The oil produced from our fingers seeps into the ridges and is left behind when we touch an object –(Locards exchange principle: we leave things behind wherever we go, and pick up things wherever we go Every contact leaves a trace Lint, hair, fingerprints, tracks, saliva, etc)
A few things about prints… Ridge patterns and the details in small areas of friction ridges are unique and never repeated. Friction ridges develop on the fetus in their definitive form before birth. Ridges are persistent throughout life except for permanent scarring. –They can not be burned or scratched off- they will grow back! Friction ridge patterns vary within limits which allow for classification.
Fingerprints AKA friction ridge patterns –b/c the ridges help increase the friction when we pick up an object, helping us hold onto it Fingerprints are the result of genetic factors and random physical stresses and tensions during development on the stratum basale, the lowest layer in the epidermis.
Print Formation Formation begins at 10 weeks after conception Is complete at 24 weeks gestation(6 mo of pregnancy) –(**some sources say complete at 14 wks)
How unique are you? Chances are one in a quintillion (1 in 100,000,000,000,000,000,000) that someone will have the same print (singular, not for all 10 fingers) as you –identical twins have similar patterns, but the prints are not the same –Boimetric identification: using fingerprints, ear prints, iris patterns to ID you, as they are each unique
The Subcutaneous Layer: The Hypodermis The hypodermis is made up of –Adipose To insulate (temperature regulation) –Loose connective tissue Collagen Elastin –Both to protect –Fibers run parallel to the skin –Rete cutaneum: network of blood vessels atborder of dermis
Hair… (a slight diversion for a moment or two…)
I went looking for a picture of hair… I found a few…
Hair Develops from a follicle –Holds the root –Nourished from dermal blood supply found in the connective tissue around the follicle –New hair cells push old hair cells up and away from the new growth –The old cells get keratinized and die
Hair Growth Cycle 90% of your hair is in a growth phase Grows 2-6 years Falls out- rests for 3 months Gets replaced by new growth –If not replaced, baldness (allopecia) Androgenic or areata Normally lose 20-100 hairs per day –Stressors can alter this
Nails Nail plate (nail itself) Nail Bed (under the nail) Lunula (half-moon area; nail grows from there Cuticle
Temperature regulation: Homeostasis (Negative Feedback) Sensory receptors (input) –thermoreceptors in skin Warm receptors Cold receptors –Hypthalamus Effectors (response) –Muscles in skin (arrector pilli) –Muscles of body –Blood vessels –Sweat (eccrine) glands Integrators –Hypothalamus (region of brain)
Temperature Regulation Radiation: primary means of loss of body heat –Heat goes out into the air Conduction: something touching your skin carries body heat away Convection: hot air from the body moves up, and cool air replaces it Evaporation: sweat (or other liquid on surface) takes heat energy to evaporate off
Too hot? You sweat to cool yourself –Eccrine glands secrete sweat –Stop sweating when you have reached an appropriate temp (negative feedback) Increase in the diameter of surface blood vessels (vasodilation) –Allows more heat from blood to escape through skin Deeper blood vessels constrict (vasoconstriction)
Extreme overheating: hyperthermia (heat exhaustion) Caused by: –Being in extreme temperature ie being trapped in a hot car (temporary, but caused by environment, not individual) –Fever (pyrexia) / illness (temporary, in normal temp environment) Attempt to kill organisms by denaturing their proteins Can kill you! Uncontrolled temperatures (above 105°F) in people, it can denature proteins (specifically enzymes) needed to survive and kill you
Dehydration a major cause of overheating ( because if you cant sweat anymore to cool off, you overheat) Symptoms of dehydration –Fatigue –Dizziness –Headache –Nausea/ vomiting –Muscle cramps
Hyperthermia, cont If sweat cant evaporate, the body cant cool itself –Reduces radiative cooling Especially if the air is hotter than the body –Reduces conductive cooling –Reduces convective cooling
Too cold? Constriction of blood vessels (vasoconstriction) near surface –Diverts blood from surface to visceral organs Hair stands on end (goosebumps- arrector pilli making hair stand up) Shivering- muscle contraction creates –Shivering is multiple repeated contractions that create a lot of heat
Skin Cancer Skin cancer is the most common form of cancer in the United States. More than 3.5 million skin cancers in over two million people are diagnosed annually. Each year there are more new cases of skin cancer than the combined incidence of cancers of the breast, prostate, lung and colon. One in five Americans will develop skin cancer in the course of a lifetime. The good news is that skin cancer is the most treatable form of cancer. Its also one of the most preventable forms.
What is skin cancer? Skin cancer is the uncontrolled growth of abnormal skin cells. It occurs when unrepaired DNA damage to skin cells (most often caused by ultraviolet radiation from sunshine or tanning beds) triggers mutations, or genetic defects, that lead the skin cells to multiply rapidly and form malignant tumors. Malignant means…very bad, threatening to a life, extremely harmful or dangerous
Melanoma, basal cell carcinomas, and squamous cell carcinomas are the most common types.
What to look for: Do a complete body check once a month, and have a dermatologist check you once a year. You are looking for any changes that fit one or more of the following: –Asymmetrical shape –Borders that are not even –Color that changes –Diameter larger than a pencil eraser –Evolution- any changes in color, size, texture, etc The earlier a skin cancer is detected, the better the chances of survival
Human skin in UV (ultraviolet) & visible light As you can see UV light behaves completely differently than visible light and shows all of the sun damage & hyper pigmentation. The melanin in the skin absorbs ultraviolet light to protect the skin. The more tan the skin, the more melanin is released from melanocytes and the more absorption of ultraviolet light occurs. You can also see that the eyes appear entirely black in the UV image, this is because eye chromophores absorb UV rays for protection against UV light damage.
Types of UV Radiation: UVA, UVB, and UVC UVA rays have the longest wavelengths, UVB have the mid level- wavelengths UVC rays which have the shortest wavelengths. UVA and UVB rays are transmitted through the atmosphere, all UVC and some UVB rays are absorbed by the Earths ozone layer. So, most of the UV rays you come in contact with are UVA with a small amount of UVB.
UVB rays reach the the epidermis only UVA rays can penetrate the dermis
Things that affect your risk for skin cancer Genetics –Family history of skin cancers –Fair skin (but darker-skinned people can also get skin cancers, too, and usually detect them later than those with fair skin. –Fair hair (red heads especially!) –Light colored eyes (blue especially) Behaviors –Sun exposure: Use of sunscreen correctly, time outside, covering up or not (including sunglasses)
Tanning? Tanning = highly increased risks of skin cancer There is NO safe amount of tanning All tanning (outdoor and tanning beds indoors) are associated with increased risks of invasive skin cancers –In fact, indoor tanning is MORE intense and concentrated than sun exposure outdoors in terms of UVA radiation, the type that causes more aging
Impacts of tanning Photo-aging can cause: –Wrinkles –Invasive cancers Even if you NEVER get a skin cancer, you will look older at a younger age when it comes to wrinkles and age spots –And while you can treat these (not cure), they are expensive and uncomfortable to treat Lasers, facelifts, and expensive creams that dont really do much
Smoking and Sun Damage- Twins Twin ATwin BTwin ATwin B
How do you reduce your risk? Seek the shade, especially between 10 AM and 4 PM. Do not burn. Avoid tanning and UV tanning booths. Cover up with clothing, including a broad-brimmed hat and UV- blocking sunglasses. Usa a broad spectrum (UVA/UVB) sunscreen with an SPF of 15 or higher every day. For extended outdoor activity, use a water- resistant, broad spectrum (UVA/UVB) sunscreen with an SPF of 30 or higher. Apply 1 ounce (2 tablespoons) of sunscreen to your entire body 30 minutes before going outside. Reapply every two hours, or immediately after swimming or excessive sweating. Keep newborns out of the sun. Sunscreens should be used on babies over the age of six months.
Factors that affect exposure Geography Altitude Time of year Time of day Weather conditions Reflection
UV Index: Provides information about the risk of UV exposure at that time; part of the weather forcast