Chapter 3

Organization of the

Body

Human Physiology

Introduction

Molecules are placed into levels of organization, or

hierarchies

Series of ordered groupings within a system

• Each level relies on properties of the lower level

Hierarchy of Human Structure

Cell – basic structural unit and functional unit of the

human body

Simplest characteristic of all organisms

• Unicellular – body comprised of one cell

• One cell must carry out all life functions (constant communication with

environment)

• Multicellular – consisting of many cells

• Cells cooperate with each other to carry out jobs

• DIFFERENTIATION

• Process by which cells mature in order to carry out the cells needs

Levels of Organization

Cell – from previous

Tissue – organized group of cells

Organ – organized group of tissues

Organ system – organized group of organs

Organism – individual biological unit capable of reproduction Any living thing

Levels of Organization, cont.

The organism is NOT the highest level of

organization

Society – groups of organisms interacting

• Outcomes of human interactions affect homeostasis

Envirome – highest level of organization

• All environmental factors that affect the survival of organisms

• Enviromics

• Study of the envirome

• Investigates the balance of the environmental conditions and processes

that affect an organisms adaptations for survival

The Human Physiological

Environment

Physiological environment – internal conditions

that optimize individual cell function and body

organization

Cells would not survive without a suitable environment

• Internal environment – condition inside the cell

• External environment – conditions outside the cell

Water

No life possible without water

Most abundant molecule in the body 55-60%

When water level falls below a certain level, the body is dehydrated State in which tissues are deprived of water

• Occurs from inadequate water in take or excessive water loss

• Diarrhea, sweating, vomiting

• Indicators are – extreme thirst, nausea and exhaustion

Overhydration – body contains too much water Termed water excess or water intoxication

• Harmful because it disrupts the physiological environment

Water, cont.

Human environment is aqueous Pertaining to water

Water is a polar molecule Polarity permits water to dissolve most of the biochemicals

needed for human survival.

Water is universal solvent Solvent – substance that dissolves other chemicals

Solute – substances that dissolves in a solvent • When a solute dissolves in a solvent, it forms a solution

• Uniform mixture of two or more substances

Water has high specific heat Energy required to raise the temperature of a substance

• Prevents the body from heating or cooling too quickly

Ions

play roles to help maintain the physiological

environment

Electrically charged particles

Classification of ions

Minerals – nutrients needed for the body

Metals – several elements that conduct heat and electricity

Cations – positively charged ions

Anions – negatively charged ions

All ions are water soluble

Most are lost by kidneys are they produce urine

2nd is sweating, then feces, and vomiting

Major Ions Related to Human

Health

Bicarbonate – fluid buffer that makes acidic conditions neutral to slightly basic Regulated by kidneys and lungs

Calcium – two forms: Diffusable – found in salts in bone

Nondiffusable – bound to blood and cell proteins

Chloride – in association with potassium and sodium Potassium chlorine (KCl) and sodium chloride (NaCl)

Copper, Iodine, and Iron help carry out chemical reactions in the cell

Major Ions Related to Human

Health, cont.

Magnesium – carries out many jobs done by calcium Critical for energy production and proper nerve function

Phosphate – body fluid buffer regulated by kidney 80% is used in the body bonds with calcium for bone

hardening

Potassium – most abundant element inside of cells Controls muscle and heart contractions

Sodium – most common mineral found outside of the cell Controls water retention

Sulfate – found as an anion attached to other moelcules Acidic, lower the pH of body fluids

STOP!!!!!

What’s the difference between

minerals and vitamins?

Difference Between Vitamins and Minerals by Laura Niedziocha, Demand Media

Everyone knows that vitamins and minerals are an essential part of a healthy diet. When part of a well-balanced diet, they provide the structure for a healthy, functioning body. You may be unaware that taking extra vitamins and minerals is unnecessary if you maintain a nutritious diet -- it may even be unsafe. You also may not know what differentiates vitamins from minerals.

Composition: Vitamins and minerals vary mostly in their composition. Vitamins are naturally occurring organic nutrients. Minerals are inorganic compounds and are smaller particles that come mostly from natural geological processes. This makes them much simpler than vitamins. Another difference in their composition lies with their solubility. Vitamins are either fat or water soluble, minerals are not.

Working Together: Any healthy and well-balanced diet assures that you are getting adequate vitamins and minerals. Although they are two different substances, many vitamins and minerals work together to maintain bodily processes. For instance, without vitamin D, calcium would not be able to promote proper bone growth.

3.2 Enzymatic Reactions and

Energy

Enzymes facilitate most of the chemical reactions

that occur in the body

Catalysts – enzymes that start reactions

Hydrolysis – chemical process of breaking down water

• Water is needed

Synthesized – process of building molecules

Reduced – process of molecule gaining or losing an

electron

Chemicals Reactions in the cell

Most reactions involve some sort of energy

transfer

Some require energy, some provide energy

Endergonic – require energy to set off and carry out

reaction

Exergonic – release cell energy

• Energy is used to build cell structures or carry out physiological

functions

Energy

Energy is the capacity for doing work

Potential energy – ability to do work food

Kinetic energy – associated with motion or action Muscle action

Body uses 4 types of energy Chemical

Electrical

Mechanical

Thermal • Calorie – used to measure body energy

• Amount of heat required to raise the temp one of gram of water 1 degree Celsius.

• Kilocalorie – food calories

• 1,000 times larger than the standard calorie.

Enzymes

Promote exergonic reactions

needed to obtain cell energy

Carry out endergonic

reactions that build body

structures or are used in cell

work

Active site

Provides attachment area

• Enzymes lock on to a substrate

molecule converting it into a molecule

called the product

Enzymes, cont.

Lock and key idea

Active site fits a particular molecule

Substrate – chemical that an enzyme modifies in

the active site

Product – result of an enzymatic reaction

Allostery – modification to allow an enzyme to work

slower or faster

Allosteric site – region of enzyme where a chemical binds

Enzymes, cont.

Other factors Competitive inhibition – chemical resembling substrate

(fake)

Feedback inhibition – enzyme’s product is not removed

Non-competitive inhibition – alter the enzymes structure or charges

pH, Electrolytes,Temperature – can alter shape of enzyme

Coenzyme – organic molecules that activate certain enzymes

Cofactor – elements or ions that facilitate enzyme activity

Molecular Transport

Membrane – separates internal from external

conditions

Sheet-like structure that surrounds and keeps the internal

environment contained

Selectively permeable membrane

• Allows certain molecules to pass, but not all

• 5 methods (each one will be discussed in detail)

• Diffusion

• Passive transport

• Active transport

• Osmosis

• Bulk mechanical transport

Diffusion

Mixing of molecules in gases and liquids as a result of thermal stirring All molecules are vibrating due to

heat • Amount of heat determines speed and

intensity

**Odors – diffusion is obvious when you open a can of something with a nasty smell

Cells depend on diffusion for essential molecules Also transports wastes from cells

Passive Transport

Diffusion that requires no cell energy

Relies on diffusion gradient as driving force

• Cell’s internal and external environments have unequal quantities

• Higher to lower = wants to even out

3 types (discussed individually)

Membrane diffusion

Facilitated diffusion

Filtration

Membrane Diffusion

Certain particles can pass through a membrane Membranes covering cell are typically lipids

• Molecules that dissolve in lipids usually have no trouble passing

• Polar molecules cannot dissolve through lipids

Hypertonic Greater quantity of a particular molecule that exists in the cell

Oxygen – moves into the cell

Hypotonic Less quantity of a particular molecule than exists in the cell

Carbon dioxide – moves out of the cell

Isotonic Equal quantity of a particular molecule in the solution in the cell

• Molecules move back and forth across the membrane in equal numbers

Nitrogen

Facilitated Diffusion

Uses a carrier protein, or channel, to move ions

and molecules through a membrane

Reserved for molecules that normally do not pass on their

own

• Slight amount of energy is used (not from the cell)

• Energy comes from carrier protein changing shape as it bonds to

transport

Only so many carrier channels available

• If all are full, the molecules pass out of the body

Osmosis

Diffusion of water across selectively permeable membrane Move from low solute to high solute(less water)

Water always moves towards the more concentrated solution

Counteracts diffusion of particles into and out of the cell Osmolarity – water’s potential to move across a membrane

Hyperosmotic – solution contains higher concentration of solute

Hypoosmotic – solution contains lower concentration than exists in the cell

Isoosmotic – equal in solute concentrations

Hypertonic vs. hypotonic

Active Transport

Requires cell energy

Useful for moving materials from an area of lower

concentration to an area of higher concentration

Works against the diffusion gradient (hence needs

energy)

2 types (will discuss in detail)

Active transport pumping

Bulk active transport

Active transport pumping

Uses proteins called pumps to move several ions

or molecules at a time across the membrane

Require energy

Consumes roughly 70% of the body’s energy

strengths

Bulk Active Transport

Moves large amounts of particles into and out of

the cells

Relies on membrane movement and modification

Endocytosis – moves particles into the cell

• Receptor-mediated endocystosis – uses a special protein on the

cell membrane (receptor) to bind specific types of molecules

Exocytosis – process of moving particles out of a cell

• Excretion – removal of waste via exocytosis

• Removal of worn out cell components

• Secretion – transport of molecules using exocytosis

• Digestive juices and mucus, nerve cell communication

STOP!

Bell Ringer

Answer the following questions on a separate

piece of paper.

What is osmolarity?

What do the terms hypertonic and hypotonic

mean?

What would happen to an individual’s red blood

cells if the osmolarity of the plasma (liquid potion of

the blood) was altered by continuous intravenous

administration of pure water (containing no

electrolytes)?

3.3 Cell Structure

Leeuwenhoek and Hooke were first to recognize

microscopic attributes of the body

Cell theory, or cell doctrine – all organisms are

made of cells

Proposed by Schleiden and Schwann in 1839

Remains foundation of modern medicine

Louis Pasteur

Showed that all essential functions of an organism occur

within cells

Cell Structure, cont.

3 structural components

Cell membrane

• Covering around the outside of cell – involved in transport

Cytoplasm

• Contents inside of cell

Genome

• Genetic material passed down from one generation to the next

Acellular Pathogens

All disease causing agents that do not use cells as

their basic unit of structure

Viruses

• Infectious agents composed of a genome (either DNA or RNA) and

a protein coat

• No ribosomes or means of protein synthesis

• Not Alive, but has living properties

Viriods

• Simply short pieces of RNA

Prions

• Puzzling – no more than a piece of protein resembling abnormal

proteins found in other organisms

Cells of Microbes

Microbes (microorganism) – must be viewed with a

microscope

Bacteria

• Most common microorganism in the human body

• Most help, do not cause disease

• Circular DNA – single-celled

• Prokaryotes – genome located in nucleoid (no nucleus), no

membrane bound organelles

• Flagella – swimming appendages

• Cell wall – made of peptidoglycan

More ex - Fungi, Protista, viruses

• Protista – malaria and sleeping sickness

Fungus

Diverse group – range from single cell to a body

mass of branched elongated/stringy cells

Single celled – yeast

Filamentous fungi – mass of stringy cells

Similar to human cells – eukaryotes

Have DNA inside the cell – specialized organelles

Most produce specialized structures

mushrooms;

Can be harmless – some fatal

Human Cells

Eukaryotic – very diverse

Fluid mosaic model – “ocean” of proteins and lipids Fluid – describes motion of proteins in the membrane

Mosaic – membrane is composed of variety of molecules

Cytoplasm – cell carries out chemical reactions for homeostasis Cytosol

• gel-like fluid composing 54% of cell volume

• Thousands of enzymes – obtain cell energy

Organelles • Perform specialized functions

Human cells, cont.

Membrane-bounded structures – manufacture and move molecules and cell parts Nuclear envelope

• Transmits genetic information

Endoplasmic reticulum (ER) • Production of protein and lipid components of cells

Golgi bodies • Modifying, storing, and shipping cell products from the ER

• Produces vesicles

Vesicles • Move products

Cell membrane

Use transport vesicles to transfer back and forth to each other

Human cells, cont.

Lysosome – recycle cell components with digesting enzymes Cause activate cell death, if needed

Programmed death cell, apoptosis Can program their own death

Vacuoles – storing materials

Mitochondria – originates from eggs cytoplasm Comes from your mother

Produce energy for the cell

Can take on different jobs depending on where they are located

Human cells, cont.

Cytoskeleton – meshwork of protein filaments and tubules in the cytoplasm that gives the cell shape and capacity for movement Coordinates the function of:

• Centrioles – assist the cell with reproduction

• Cilia - Hairlike processes on cell membrane capable of motion

• Flagella – found only on sperm, gives ability to move in body fluids

Nucleus – more like instruction manual, than brain With few exceptions, nucleus carries the genetic material of

the entire genome

Main role – genetic expression • Genetic material’s coded information is used to produce cells

structures and carry out cell physiology

STOP

Bell Ringer

Place this answer in your notes.

In terms of energy conversion (going from one type

of energy to another) how is the energy needed by

a weight lifter created, and what type of energy

does his/her activity create?

Use chemical energy, electrical energy, mechanical

energy and thermal energy in your answer.

Tissues (3.4)

As the fetus develops, groups of cells are

organized into functional units called tissues

First three to form – embryological germ layers

Ectoderm – outer layer, forms the skin and brain

Mesoderm - middle layer, builds bone and muscle

Endoderm – innermost, produces the digestive organs

Stem cells – retain their ability to undergo cell

division

Assist further development and healing later in life

Tissues, cont.

Each germ layer responsible for each of the four

human tissue types

Epithelial

• Forms layers of cells that line body cavities creating coverings over

external and internal body structures

Connective

• Supports the framework of the organs and the body

Muscle

• Contractile tissue that provides the body with movement

Nervous

• Highly specialized – capable of conducting and coordinating body

information

Epithelial Tissue

Come in a variety of shapes and arrangements Determined by function

Simple – single layer Squamous – thin coverings – flat

Cuboidal – cube-shaped associated with structures that produce secretions

Columnar – tall – involved in secretion and uptake of materials

Stratified – multi-layered arrangments – subject to wear and tear (skin)

Pseudostratified – only has single layer – gives impression that it is stratisfied

Transitional – occurs in places of stretch and expansion Cells change from columnar to squamos

Some are ciliated – have cilia

Simple Columnar

Simple Cuboidal

Simple Squamos

Ciliated Pseudostratified Epithethial

Stratified Squamos Transitional

Connective Tissue

Composed of cells throughout a matrix of gel, liquid, protein fibers, or salts Common proteins found in connective tissue

• Collagen – strength

• Elastin – flexibility

• Reticulum – support

Classified as loose or dense Loose – most abundant type found in the body

• Provides attachment, stabilization, structure, and support

• Ex – blood

Dense • Strength – bone and cartilage

• Storage – adipose(fat)

• Flexibility – ligaments and tendons

LOOSE DENSE ADIPOSE

Muscle Tissue

Consists of cells with cytoskeleton fibers organized into bands or bundles that contract to cause body movement

Three types: Smooth – made of spindle or tear-drop shaped cells where

fibers are not visible • Provide weak contractions, found in the linings of blood vessels and

tubular organs

Cardiac – striated – fibers lined up as visible bands • Connected by intercalated disks

• heart

Skeleton • Large cells with distinct striations with provide strong directional

movement

• Attach to bones and joints – produces body movement

Muscle Tissue, cont.

Voluntary Under conscious control – skeletal muscles

You choose movements

Involuntary Work without conscious effort

• Heart

Striated Skeletal & cardiac

Non-striated Smooth muscle

Skeletal Muscle

Ways to identify:

Striated – no

intercalated discs

Each cell, many

nuclei

SmoothMuscle

Ways to identify:

No Striations

Each cell, single

nucleus

Cardiac

Ways to identify:

Straitions

Intercalated Discs

Nervous Tissue

Composed of two highly specialized cells Neurons

• Nerve cells – made up of a nerve cell body and various extensions from cell body that produce electrical impulses

• Motor neuron

• Sensory neuron

• interneuron

Neuroglia • Not involved in conduction of impulses

• Types

• Astrocytes – provide organization and support for nervous system

• Oligodendrites – from sheaths called myelin around neuron fibers

• Myelin speeds up transmission of nerve impulses

• Ependymal cells – secrete fluids that protect the brain

• Microglia – believed to maintain ion balance needed for nerve cell function

STOP!

3.5 Organs & Organ Systems

(pgs 112-121)

Organs are groups of tissues that work together to perform a function Organs working together = organ system

Cardiovascular – regulates blood flood

Digestive – regulates nutrition

Endocrine – regulates body function and development

Integumentary – provides protection

Lymphatic – regulates body fluids, helps fight disease

Muscular – provides structure and movement

Nervous – regulates flow of information

Reproductive – regulates sexual function

Respiratory – regulates atmospheric gases and certain bodily wastes

Skeletal system – provides support and movement

Urinary – regulates production, storage, and removal of urine

Organ Systems

Be sure to check out the images on page 113-

118….

Those images match up some body parts to which

system they belong to.

Use this as a reference for test

Wellness and Illness over the

Life Span

Cell pathology is basis of dysfunction

Abnormal, impaired, or incomplete functioning of a part of

the body’s hierarchy.

• Almost all gross diseases are due to dysfunction

Biopsy – surgical removal of diseased cells for

study

Cell Pathology conditions

Amyloid deposition (amyloidosis) – accumulation of amyloids in a cell Amyloid – protein-like material

• Indicators of cell damage • Intended to help, but cause harm when they build up

• Can cause cell death • EX – Alzheimer’s

Atrophy – wasting or decrease in size of cell, tissue, or organ Causes undernutrition and blood flow problems

Dysplasia – disorderly growth pattern in a tissue or organ

Dystrophy – “ill growth” Caused by malnutrition, undernutrition, or decreased blood

flow

Cell Pathology conditions, cont.

Fatty change – accumulation of lipids in the cell in response to cellular injury Excessive alcohol intake – leads to build up in liver cells

Hyperplasia – abnormal multiplication on the number of normal cells in a tissue Increases risk of cancer

Hypertrophy – enlargement of a tissue or organ

Metaplasia – abnormal change in cell and tissue function

Metastasis – cancerous or highly abnormal cells Cells break away from where there are supposed to be and move to

other locations in the body

Necrosis – localized tissue death From decreased blood flow, infections, injury, etc.

Cellular Aging

Fat cells, skeletal muscle and nervous tissue do

not undergo mitosis

Mitosis not only replicates cells, but also repairs cells

Cells accumulate damage over the years

Accumulated cell damage

• Eventually, the cells will fail at their task

Stress even causes cell aging

Releases certain hormones

Cellular Aging

Even cells that regularly replicate undergo damage

DNA can become damaged in the S(synthesis) phase of

mitosis

Every round of mitosis shortens the ends of the

chromosomes – called telomeres

They do not carry genes, but too much shortening can

make the structure abnormal

• Malfunction or cell death

Cancer cells do not go through telomere

shortening, they are immortal.