The Human Body: an orientation

anatomy

the study of the structure and shape of the body and it's parts and their relationship to one another

gross anatomy

large, easily observable structures

ana-

apart

-tomy

to cut

microscopic anatomy

the study of body structures that are too small to be visible with the naked eye

examples of microscopic anatomy

cells and tissues

physio-

nature

-ology

the study of

neurophysiology

explains the workings of the nervous system

cardiac physiology

studies the function of the heart

structural ladder (simplest to complex)

atoms, molecules, cells, tissues, organ, organ system, organizm

atom

tiny building block of matter

molecules

groups of atoms held together by bonds

cells

made of molecules; the smallest units of living things; have common structures and functions, but can vary widely in size, shape, and role in body

tissues

groups of cells that have a common function

the four tissue types

connective, epithelial, muscle, nervous

organ

a structure composed of two or more tissue types that performs a specific function for the body

organ system

a group of organs that work together to accomplish a common purpose

organism

the 11 organ systems that make up living beings; sum of all structural levels working together to keep us alive

integumentary system

the external covering of the body, or skin. includes hair and nails

functions of integumentary system

This system waterproofs the body and cushions and protects the deeper tissues from injury, produces Vitamin D with sunlight, excretes salt in perspiration, helps regulate body temperature, and has sensory receptors located in the skin that alert us to what is happening at the body surface.

skeletal system

consists of bones, cartilages, and joints

skeletal system functions

This system supports the body, provides a framework that the skeletal muscles use to cause movement, has protective functions, forms blood vessels in cavities of the skeleton, and the hard substances of bone act as a storehouse for minerals.

muscular system

only function is to contract and shorten to produce movement

skeletal muscles

They are the large, fleshy muscles attached to bones. The mobility of body as a whole relies on these muscles.

nervous system

The body's fast acting control system

organs of the nervous system

the brain, spinal cord, nerves, and sensory receptors

sensory receptors

These receptors detect changes in temperature, pressure, sound, or light, then send messages via nerve impulses to the central nervous system

nerve impulses

electrical signals

central nervous system

brain and spinal cord; assesses nerve impulse's information and responds by activating the appropriate body effectors

body effectors

muscles or glands, which are organs that produce secretions

endocrine system

controls body activities, but acts more slowly than the nervous system

function of endocrine system

endocrine glands produce chemical molecules called hormones and release them into the blood to travel to relatively distant target organs

endocrine glands

pituitary, thyroid, parathyroid, adrenal, thymus, pancreas, pineal, ovaries (F), and testes (M) glands

cardiovascular system

uses blood as a carrier to deliver oxygen, nutrients, hormones, and other substances to, and pick up waste such as carbon dioxide from, cells near sites of exchange

primary organs of the cardiovascular system

the heart and blood vessels

function of heart

propels blood out of its chambers into blood vessels to be transported to all body tissues

white blood cells

help to protect the body from foreign invaders such as bacteria, viruses, and tumor cells

lymphatic system

when fluid is leaked into tissues from the blood, lymphatic vessels return it to the blood stream so there is enough blood to continuously circulate the body

organs of the lymphatic system

lymphatIc vessels, lymph nodes, spleen, and tonsils

function of lymph nodes

cleanse the blood and house white blood cells involved in immunity

respiratory system

keeps body supplied with oxygen and removes carbon dioxide

organs of the respiratory sysyetm

the nasal passages, pharynx, larynx, trachea, bronchi, and lungs

how lungs function

the lungs have tiny air sacs where gases are exchanged with blood through thin walls

digestive system

breaks down food and delivers the resulting nutrients to the blood to be dispensed to body cells

main digestive organs

the oral cavity, esophagus, stomach, small and large intestine

accessory digestive organs

liver, salivary glands, and pancreas

urinary system

removes the nitrogen-containing waste

cause of nitrogen containing waste

Nitrogen-containing waste (urea and uric acid) results from the breaking down of proteins and nucleic acid, which are genetic information molecules

organs of the urinary

the kidneys, ureters, bladder, and urethra

functions of urinary system

removes nitrogen-containing waste, maintains the body's water and salt (electrolytes) balance, regulates the acid-base balance of the blood, and helps to regulate normal blood-pressure

reproductive system

produces offspring

male reproductive organs

the scrotum, penis, accessory glands, and the duct system which carrier sperm to the outside of the body

female reproductive organs

the ovaries, uterine tubes, uterus, and vagina

uterus

provides the site for the development of the fetus once fertilization occurs

maintaining boundaries

living organisms must be able to maintain boundaries so that it's insides remain distinct from its outside

how boundaries are maintained

every cell in the human body is surrounded by an external membrane that separates its contents from the outside interstitial fluid and allows entry of needed substances while generally preventing entry of potentially damaging or unnecessary substances. the body as a whole is enclosed by the integumentary system

role of integumentary system

protects vital organs from drying out, pathogens, and the damaging effects of heat, sunlight, and chemical substances in the external environment.

movement

Includes all activities promoted by the muscular system. the skeletal system provides the bones that the muscles pull on as they work. movement also occurs when substances such as blood, foodstuffs, and urine are propelled through the internal organs

responsiveness

the ability to sense changes in the environment and then to react to them

what organ system is most responsible for responsiveness?

Nerve cells are highly irritable and can communicate rapidly with one another, so the nervous system bears the major responsibility for responsiveness. However, all body cells are responsible to some extent.

digestion

The process of breaking down ingested food into simple molecules that can then be absorbed into the blood. the nutrient rich blood is then distributed to all body cells via the cardiovascular system. the simple nutrient molecules are then used for energy and raw materials.

metabolism

all chemical reactions that occur within the body

what does metabolism include?

it includes breaking down complex substances into simpler building blocks (digestion), making larger structures from smaller ones, and using nutrients and oxygen to produce molecules of adenosine triphosphate (ATP)

Adenosine Triphosphate (ATP)

energy rich molecules that power cellular activities

what systems does metabolism rely on?

It depends on the digestive and respiratory systems to make nutrients and oxygen available to the blood and on the cardiovascular system to distribute these needed substances throughout the body. It is also regulated by hormones secreted by glands of the endocrine system.

excretion

the process of removing excreta (waste) from the body

what organ systems participate in excretion?

the digestive system rids the body of indigestable food residues in feces, the urinary system disposes of nitrogen-containing wastes, and the skin disposes of various waste products as components of sweat

reproduction

the production of offspring, can occur on the cellular or organismal level

cellular reproduction

in this form of reproduction, the original cell divides, producing two identical daughter cells that may then be used for body growth and repair

human reproduction

when a sperm unites with an egg, a fertilized egg forms, which develops into a baby within the mother's body. this is regulated very precisely by the endocrine system

growth

increase in cell size or body size, which is usually accomplished by an increase in the number of cells

how does growth occur?

for growth to occur, cell construction activities must occur at a faster rate than cell destruction

survival needs

nutrients, oxygen, water, and appropriate temperature and atmospheric pressure

nutrients

nutrients are taken in through food and contain the chemicals used for energy and cell building

carbohydrates

the major energy providing fuel for body cells

proteins

are essential for building cell structures

fats

to a lesser extent than proteins, fats are essential for building cell structures. fats also cushion body organs and provide reserve fuel

minerals and vitamins

required for the chemical reactions that go on in cells and are for oxygen transport in the blood

what is necessary for nutrients to be useful?

For nutrients to be useful, oxygen must be present, as the chemical reactions that release energy from foods require oxygen. This is why human cells can only survive for a few minutes without it.

water

The single most abundant chemical substance in the body and provides the fluid base for body secretions and excretions

What percent of body weight is water?

water accounts for 60-80% of body weight, depending on the age of the individual.

how is water obtained and lost?

Water is obtained chiefly from ingested foods or liquids and is lost by evaporation from the lungs and skin and in body excretions.

normal body temperature

the body temperature of 98.6 F (37 C) is necessary for chemicals reactions to continue at life sustaining levels. if the body temp drops below this, metabolic reactions become slower and slower and finally stop. if the body temperature is too high, chemical reactions proceed too rapidly, and body proteins begin to break down

how is most body heat gained?

most body heat is generated by activity of the skeletal muscles

how is most body heat lost?

Most body heat is dissipated via blood circulating close to the skin surface or by the evaporation of sweat.

atmsopheric pressure

the force exerted on the surface of the body by the weight of air

what functions depend on atmospheric pressure?

breathing and the exchange of oxygen depend on appropriate atmospheric pressure. at high altitudes, where the air is thin and atmospheric pressure is lower, gas exchange may be too slow to support cellular metabolism.

connective tissue

primarily made of collagen; protects, structures, supports, and anchors organs in the region they function

How does your body function?

Each part has a job to make the body operate.

What does structure determine?

Functions an organ can perform.

What does the structure of the lungs allow them to do?

Exchange gases and provide oxygen.

What is the simplest living creature made of?

Single-celled organisms.

What does the small intestine do? What type of tissue is it made of?

Digests and absorbs food. Made of all four tissue types.

How do the heart and blood vessels work together?

Circulate blood to carry nutrients and oxygen.

What makes endocrine glands different from other organ systems?

Not connected anatomically, secrete hormones.

What are some examples of processes controlled by hormones?

Growth, reproduction, nutrient use by cells.

How does the digestive system function?

Tube from mouth to anus, breakdown and absorption of food.

Why is the liver considered a digestive organ?

Produces bile to break down fats.

What organ has both digestive and endocrine functions?

Pancreas.