Human Physiology

By Sydney Hollingshead

Biology

Mr. Thiel

7 period

4/23/07

Skeletal

Function

Supports body Protection for organs Allows wide range of motion Place for muscles to attatch Stores mineral reserves Site for blood cell formation

Structures

Bone Stiff, brittle, dense outer and soft inner Has blood cells and nerves running through

Cartilage Flexible, supportive connective tissue - cushions bones

Ligaments Tough connective tissue - hold bones together

Tendon Tough connective tissue - holds skeletal muscles to bones

Marrow Inside bone cavities in center, soft tissue, yellow + red

Process

Strong bones hold up body and deflect damage to organs Muscles attatch w/ tendons Bones store calcium

When excess calcium in body, bones take it out of blood, grow or store When not enough, body needs more, takes out of bones, bones become weaker, more

brittle (Osteoperosis) Joints provide motion, versus shell or exoskeleton which limits motion Red marrow produces blood cells

Circulatory

Structures

Heart Blood vessels Blood

Function

Brings oxygen, nutrients, hormones to cells Fights infection Regulates body temperature

Process

Heart Pumps blood throughout the body Four chambers allows two seperate pathways for blood blood with different amounts of oxygen and carbon dioxide won’t mix

together,oxygenated blood is sent to muscles and CO2 blood sent to lungs Arteries

Large vessels, carry blood to tissues, oxygen-rich blood Thick walls, can expand under pressure Smooth muscle in arteries control diameter

Viens, cappilaries, blood cells, platelets,

Process continued

Capillaries Smallest blood vessels Closest to cells of body, passes nutrients, oxygen, absorbs CO2 and

other waste, taken back to heart and into lungs to be disposed of(standard 1a)

Thin walls (one cell thick) help nutrients pass through Veins

Bring blood away from body, back to heart One-way valves help contain blood against gravity Skeletal muscles squeeze veins to push blood back to heart

Process continued

Blood Cells Red blood cells (most common) transport oxygen

Contain hemoglobin to bind to oxygen Produced in red marrow, destroyed in Liver and Spleen Doughnut shape, fill with hemoglobin and force out organelles

White Blood Cells attack foreign substances and organisms Don’t have hemoglobin Made in red marrow, body can drastically increase number of white blood

cells when fighting an infection Also called phagocytes(eating cells), engulf and digest foreign cells (i.e.

cancer cells, allergies, transplanted organs) Platelets - fragments of marrow enclose in cell membrane, released into

bloodstream Aids in blood clotting

Nervous

Structures

Brain Spinal Cord Peripheral Nerves Neurons, impulses, synapses

Function

Coordinates body’s response to changes in internal + external environments Utilizes feedback loops to achieve homeostasis

Ex. – Body temperature When temp. drops, involuntary actions occur – appendages are drawn

into the body, goosebumps (make “fur” stand up and trap air against body for insulation), shivering

When temp. increases, brain tells body to slow down, stop movement, lethargy occurs, so body won’t overheat

Ex. – Bones draw calcium from bloodstream or release back into bloodstream when needed

Standard 1c

Process

Carries messages to body from brain Brain = control center

Cerebrum = voluntary actions Cerebellum = coordinates + balances motion Brain Stem = connects brain + spinal cord, regulate information flow, blood

pressure, heart rate, breathing, swallowing Spinal Cord = major telephone line

Main link from brain to rest of body Controls reflexes

Process continued

Peripheral nerves Sensory(senses)

Alert the brain to surroundings Pain in sensory receptors send message to central nervous system and

back to motor division, causing movement of muscles to remove the body from pain source

Motor(movement) division Motor = somatic and autonomic

Somatic = conscious movement, some reflexes Autonomic = involuntary(heartbeat, digestion)

Sympathetic and parasympathetic create a feedback loop

Standard 1bStandard 1c

Process continued

Neurons Transmit electrochemical impulses(messages)

Sensory neurons send impulses from sensory organs to the brain/spinal cord

Motor neurons send impulses from brain/spinal cord to muscles and glands

Interneurons carry impulses between sensory and motor neurons Standard 1d Standard 1e

Muscular

Structures

Skeletal Muscle Smooth Muscle Cardiac Muscle

Function

Produces voluntary movement w/ help of skeletal system Helps circulate blood Helps move food through digestive system

Process

Muscles produce contraction through chemical processes Skeletal muscles control most voluntary movement Skeletal muscles attatch to bones by tendons, and pull on bones like

levers Joint = fulcrum Muscle = force

Most muscles work in opposing pairs Muscle movement helps push oxygen-depleted blood away from

limbs and back to heart against gravity(with prolonged rest, muscles become “tingly”, due to lack of new, oxygenated blood)

Muscular Contraction

Nerve impulse Ca+ released in Endoplasmic Reticulum Ca+ activates use of ATP by Myosin Myosin uses ATP to attach to actin Filaments and pull together

Standard 1h

Digestive

Structures

Mouth Pharynx Esophagus Stomach Small/large intestines

Function

Converts foods into simpler molecules that can be used by the cells of the body Absorbs food

Process

Consumption is necessary – must obtain energy to operate chemical reactions in the body

Mouth begins mechanical digestion by breaking down food into fine paste – molecules are split apart by force

Digestive enzymes(amylase) in saliva begin chemical digestion – molecules themselves are broken down (standard 1f)

Pharnyx = passageway to esophagus Esophagus = uses muscles to push chewed food into stomach

Process continued

Stomach Stomach acid(hydrochloric), makes stomach contents acidic

Triggers pepsin enzyme, pepsin+hydrochloric acid begins protein digestion (standard 1f)

Pancreas/Liver Pancreas produces more enzymes(lipases, proteases, nucleases) and

neutralizes stomach acid so these enzyme’s won’t be destroyed Liver produces bile(fluid containing lipids and salts), dissolves pockets of

fat in fatty foods so enzymes can better break down fat molecules (standard 1f, 1g)

Process continued

Small Intestine Most chemical digestion is complete Small intestine absorbs nutrients through villi

Large Intestine Food is mostly nutrient-free Removes water from indigestible material left

Reproductive

Structures

Testes Epididymis Vas deferens Urethra Penis Ovaries Fallopian Tubes Uterus Vagina

Function

Produces reproductive cells (females) nurtures, protects developing embryo

Process

Males Sperm are produced in testes

Cells in testes undergo meiosis to form haploid structure Sperm move into epididymis to fully mature and be stored Move to vas deferens, into urethra, then to penis

Sperm are released through ejaculation(regulated by autonomic nervous system)

Process continued

Female Begins in ovaries, where follicles(immature egg) are contained Under influence of FSH and estrogen, follicle gets larger and

undergoes meiosis Ovulation occurs – follicle breaks open and egg is released into a

Fallopian tube(can be fertilized here) After a few days, enters uterus

Uterine lining develops, and blood supply increases to receive the egg

Process continued

If egg was fertilized, division begins After several divisions, egg(now called blastocyst) implants into uterine

lining Development begins – after thousands of divisions, cells begin to

specialize and form systems, now called embryo Placenta is formed in uterus – connects mother and embryo, provides

nutrition and waste removal If egg was not fertilized, menstruation begins

Uterine lining breaks down, discharged, along with blood and egg, through vagina

Endocrine

Structures

Hypothalamus Pituitary Thyroid Parathyroids Adrenals Pancreas Ovaries testes

Function

Controls: growth development metabolism reproduction

Process

By use of hormones released into bloodstream from glands throughout the body, messages are broadcast throughout the body and stimulate certain events

Internal Feedback Mechanisms Ex. When hypothalamus senses low levels of thyroxine in blood,

sends a hormone into bloodstream that only target cells in pituitary can receive, which produces another hormone sent to the thyroid gland which produces thyroxine.

Presence of thyroxine in blood inhibits production of initial hormone from hypothalamus

Standard 1i

Process continued

Feedback loop Blood Sugar

When gets high, pancreas releases insulin to make cell walls more permeable to sugar, cells take in excess sugar

When gets low, liver releases glucagon, stored sugar Standard 1c

Excretory

Systems

Skin Lungs Kidneys Ureters Urinary bladder Urethra

Function

Eliminates waste products of metabolism from body Maintains homeostasis

Process

Blood passes through the kidney and waste products are trapped and excreted as urine

Many nutrients are returned to the blood after filtration through reabsorption Regulatory hormones are released due to the composition of the blood

Ex. When you eat salty food, kidney will respond by letting less salt return to the blood through reabsorption (standard 1g)

Process continued

Skin excretes water, salts, and urea through sweat Lungs excrete carbon dioxide

Blood returns carbon dioxide from body/heart through capillaries in lungs, receive oxygen and return to heart/body (standard 1a)

Lymphatic

Systems

White blood cells Thymus Spleen Lymph nodes Lymph vessels

Function

Helps protect body from disease Collects fluid lost from blood vessels and returns fluid to circulatory system

Process

White blood cells attack foreign substances/organisms Network of vessels collect lymph(fluid lost by blood)

Collects in lymphatic capillaries, slowly move into larger vessels, prevented from backwards flow by valves

Returned directly to heart Lymph nodes filter lymph

Trap bacteria + disease-causing micro-organisms Become “swollen” with large amounts

Nodes also absorb fat and fat-soluble vitamins from intestines and put it directly into blood

“Immune System”

Skin provides first, nonspecific defense against disease (standard 2a) Dead skin cells are hard to penetrate Oil + sweat create an acidic environment

Antibodies destroy pathogens that enter body through wounds or otherwise When attached en masse to an antigen, attract white blood cells to engulf

entire mass

“Immune System” continued

Vaccinations introduce mild forms of a pathogen Stimulates body to create specific antibodies while not being strong

enough to harm the human Bacteria V.S. Virus

Bacteria reproduce through division Viruses inject their DNA into another cell to reproduce

Bacteria are “swallowed” by white blood cells Because Viruses takeover cells native to the body, the immune system

does not recognize them as foreign, and they are not attacked Bacteria can be treated through medical immune system boosters and

otherwise Viral infections cannot be treated after infection occurs; vaccinations

can be given, but viruses mutate and then the vaccination is ineffective

“Immune System” continued

Phagocytes = white blood cells Consume bacteria + other foreign objects

B-lymphocytes Produce antibodies

T-lymphocytes Assist and regulate release of antibodies Attack antigen-bearing cells directly

Respiratory

Structures

Nose Pharynx Larynx Trachea Bronchi Bronchioles Lungs

Function

Provides oxygen needed for cellular respiration Removes excess carbon dioxide from body

Processes

Air is sucked into mouth/nose Passes through pharynx and into trachea (windpipe) – larynx produces sound Air enters bronchi, then to lungs

Bronchi divides into bronchioles, then into dead ends called alveoli Each alveoli surrounded by net of capillaries, where gas exchange takes

place Diaphragm

Lungs are sealed into sacs, airtight Diaphragm pulls/pushes at bottom of sacs, forces air in or out Chest wounds can puncture airtight sacs and breathing won’t occur

Integumentary

Systems

Skin Hair Nails Sweat/oil glands

Function

Barrier against infection/injury Regulates body temperature Provides protection against UV radiation

from sun

Processes

Epidermis keeps out bacteria and other outside dangers - waterproof

Dermis Blood vessels can narrow/widen to conserve/release heat Sweat removes heat from your body when it evaporates Oil secretions keeps epidermis flexible/waterproof

Hair Protects scalp from UV rays, cold insulation Nostril/ear canal/eye hair keeps out dirt

Nails Protect end of fingers/toes

                                                                                                                                                           

    

Bibliography

Miller, Kenneth and Joseph Levine. Biology. New Jersey: Prentice Hall, 2002.

Thiel, Eric. Biology teacher, Amador Valley High School. Lecture. 17 Apr. 2007.

Standards

1a. Students know how the complementary activity of major body systems provides cells with oxygen and nutrients and removes toxic waste products such as carbon dioxide

1b. Students know how the nervous system mediates communication between different parts of the body and the body’s interactions with the environment

1c. Students know how feedback loops in the nervous and endocrine systems regulate conditions in the body.

1d. Student know the functions of the nervous system and the role of neurons in transmitting electrochemical impulses

1e. Students know the roles of sensory neurons, interneurons, and motor neurons in sensation, thought, and response

1f. Students know the individual functions and sites of secretion of digestive enzymes, stomach acid, and bile salts

1g. Students know the homeostatic role of the kidneys in the removal of nitrogeneous wastes and the role of the liver in blood detoxification and glucose balance.

1h. Students know the cellular and molecular basis of muscle contraction, including the roles of actin, myosin, Ca+2, and ATP

1i. Students know how hormones provide internal feedback mechanisms for homeostasis at the cellular level and in whole organisms.

Standards cont.

2a. Students know the role of the skin in providing nonspecific defenses against infection

2b. Students know the role of antibodies in the body’s response to infection 2c. Students know how vaccination protects an individual from infectious

diseases 2d. Students know there are important differences between bacteria and viruses

with respect to their requirements for growth and replication, the body’s primary defenses against bacterial an viral infections, and effective treatments of these infections.

2e. Students know why an individual with a compromised immune system may be unable to fight off and survive infetions by microorganisms that are usually benign

2f. Students know the roles of phagocytes, B-lymphocytes, and T-lympocytes in the immune system