unit 1: levels of organization
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Unit 1: Levels of Organization. Chapter 1: Introduction to Human Anatomy and Physiology. Additional Historical points to Ponder (1.1). Primitive people were hunter-gatherers. Killed when hungry and ate their kills - PowerPoint PPT PresentationTRANSCRIPT
UNIT 1:LEVELS OF ORGANIZATION
Chapter 1: Introduction to Human Anatomy
and Physiology
ADDITIONAL HISTORICAL POINTS TO PONDER (1.1)
Primitive people were hunter-gatherers.Killed when hungry and ate their kills
Gathered wild plants which contained and provided chemicals that naturally fought infections
ADDITIONAL HISTORICAL POINTS TO PONDER
• Introduction of Agriculture• Brought exposure to pin, hook,
and tape worms in the fertilizer – animal manure• The ability to grow crops
lessened the need to rely on wild plants. This decreased the ability to fight infections naturally through the chemicals in the wild plants
ADDITIONAL HISTORICAL POINTS TO PONDER
• Urbanization• Leaving the country and
forming towns increased the number and severity of infectious illnesses as well as malnutrition• People became sedentary and
altered their diets• Evidence documented in
bones and teeth (p. 11)
LEARNING OUTCOME 1.1
Identify some of the early discoveries that lead to our current understanding of the human body.
Ana- (up) + -tomy (to cut or break) = AnatomyThe study of the structure (morphology
and form) of body partsLiterally to cut up or break apart the
body into its partso Physio- (relationship to nature) + -ology (to
study) = Physiology• The study of the function of body parts
• What they do and how they do it – the study of what and how each body part does naturally
ANATOMY & PHYSIOLOGY (1.2)
ANATOMY & PHYSIOLOGYThese 2 sciences
are very closely related
Structure determines functions; therefore
ANATOMY DETERMINES PHYSIOLOGY
ULTRASONAGRAPHY
MAGNETIC RESONANCE IMAGING (MRI)
CT IMAGING
LEARNING OUTCOME 1.2
Explain how anatomy and physiology are related.
LEVELS OF STRUCTURAL ORGANIZATION (1.3)
Subatomic particles
ProtonsNeutronsElectrons
Subatomic particles
Atom The smallest particle of an element
Subatomic particles
Atom
MoleculeA particle composed of 2 or more joined atoms
Subatomic particles
Atom
Molecule
Macromolecule A large molecule composed of lots of molecules – lipids, carbohydrates, DNA
Macromolecule
Subatomic particles
Atom
Molecule
Organelle
A small organ of a cell which performs a particular function
Subatomic particles
Atom
Molecule
Macromolecule
Organelle
Cell
The basic unit of structure and function of living organisms
Subatomic particles
Atom
Molecule
Macromolecule
Organelle
Tissue
A group of similar cells that performs a specialized function
Subatomic particles
Atom
Molecule
Macromolecule
Organelle
Cell
Organ
A structure consisting of a group of tissues that performs a specialized function
Subatomic particles
Atom
Molecule
Macromolecule
Organelle
Organ system
A group of organs that act together to carry out a specialized function
Organ system
Subatomic particles
Atom
Molecule
Macromolecule
Organelle
CellTissue
Organism
The most complex level of
organization – an
individual living thing
LEARNING OUTCOME 1.3
List the levels of organization in the human body and the characteristics of each
10 CHARACTERISTICS OF LIFE (1.4)
Movement- change in position of the body or body part; motion of an internal organ
Responsiveness- reaction to a change inside or outside the body
Growth- increase in size without a change in general shape
Reproduction- production of offspringDigestion- process of breaking down foodExcretion- process of removing waste
10 CHARACTERISTICS OF LIFEo Respiration – exchange of gases between the
atmosphere and the body cellso Absorption – passage of substances through
membranes and into body fluidso Circulation – movement of substances in body
fluidso Assimilation – chemically changing absorbed
substances in the body
These processes that obtain, release, and use energy are largely metabolism – all the chemical reactions in an organism that support life.
LEARNING OUTCOME 1.4
List and describe the major characteristics of life
Give examples of metabolism
MAINTENANCE OF LIFE (1.5) Nutrients- chemicals used for energy and cell
building Oxygen- chemical reactions that release energy
from foods require oxygen – cellular respiration Water- 60 to 80 % of the body weight – for most
metabolic reactions, lubrication Heat – needed to maintain body temperature-
98.6°F Too low: metabolic reactions slow down until they stop Too high: metabolic reactions speed up until proteins all
break down Atmospheric Pressure- weight of air – needed for
breathing and filtering blood through the kidneys
HOMEOSTASIS The body’s maintenance of a relatively stable
internal environment despite external changes• This is done by keeping conditions in a
homeostatic range compatible with life, near a “set point” value
Most life processes and metabolic reactions work to maintain homeostasis
HOMEOSTASISINTERNAL ENVIRONMENT
o Anatomically – the conditions inside the body but surrounding the cells (outside)
o Cells act in ways that keep the internal environment relatively constant and stable
o Consists of fluid that surrounds cells (extracellular fluid)
o Protects our cells from external changes that would kill isolated cells
HOMEOSTASISAll homeostatic mechanisms – self-regulating control systems - have three components in nature
1. Receptor – senses change in the environment
2. Control Center – regulates set point of variables
3. Effector – organ that acts in response to changes
HOMEOSTASIS
5. Response – return to homeostasis(Change is corrected.)
1. Stimulus(Change occursin internalenvironment.)
(Change is comparedto the set point.)
Control center(set point)
Effectors(muscles or glands)
Receptors(sensor)
3. Input information sent along afferent pathway
2. Change detected by receptor
4. Output information sent along efferent pathway to activate
HOMEOSTASIS Most homeostatic mechanisms are regulated
by negative feedback – brings conditions back toward set point - Automatic (regulates body temp, heart rate, blood pressure, breathing rate, blood levels of: oxygen, glucose, carbon dioxide, minerals)
Sometimes conditions are purposely moved away from the set point – positive feedback - RARE in human body Control events that happen explosively “fight-or-flight”, childbirth, blood clotting
HOMEOSTASISNEGATIVE FEEDBACK
Control centerThermostat detectsdeviation from setpoint and signalseffectors.
ReceptorsThermostat inroom detects change.
too high
Normal roomtemperature
Thermostatset point
too low
EffectorsHeater turns on;air conditionerturns off.
Control centerThermostat detectsdeviation from setpoint and signalseffectors.
ReceptorsThermostat inroom detects change.
StimulusRoom temperaturedrops below set point.
ResponseRoom temperaturereturns toward set point.
EffectorsHeater turns off; airconditioner turns on.
StimulusRoom temperature risesabove set point.
ResponseRoom temperaturereturns towardset point.
HOMEOSTASISPOSITIVE FEEDBACK
Control centerThe hypothalamusdetects the deviationfrom the set point andsignals effector organs.
ReceptorsThermoreceptorssend signals to thecontrol center.
EffectorsSkin blood vesselsdilate and sweat glandssecrete.
too high
too low
Normal bodytemperature37°C (98.6°F)
ReceptorsThermoreceptorssend signals to thecontrol center.
EffectorsSkin bloodvessels constrictand sweat glandsremain inactive.
Control centerThe hypothalamusdetects the deviationfrom the set point andsignals effector organs. If body temperature
continues to drop,control center signalsmuscles to contractinvoluntarily.
StimulusBody temperaturerises above set point.
StimulusBody temperaturedrops below set point.
ResponseBody heat is conserved, temperaturereturns toward set point.
ResponseBody heat is lost tosurroundings, temperaturereturns toward set point.
35
ANIMATION: POSITIVE AND NEGATIVE FEEDBACK
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HOMEOSTATIC IMBALANCE
Disturbance in homeostasis occursAs we age our body organs become less
efficient and our internal conditions become less stable.
Any disease or abnormal condition in the body.
LEARNING OUTCOME 1.5 List and describe the major
requirements of organisms Explain the importance of
homeostasis to survival Describe the parts of a homeostatic
mechanism and explain how they function together