1 the human body: an orientation p a r t a. overview of anatomy and physiology anatomy – the...
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The Human Body: An Orientation
P A R T A
Overview of Anatomy and Physiology Anatomy – the study of the structure
of body parts and their relationships to one anotherGross or macroscopicMicroscopicDevelopmental
Physiology – the study of the function of the body’s structural machinery
Gross Anatomy
Regional – all structures in one part of the body (such as the abdomen or leg)
Systemic – gross anatomy of the body studied by system
Surface – study of internal structures as they relate to the overlying skin
Microscopic Anatomy
Cytology – study of the cell Histology – study of tissues
Developmental Anatomy
Traces structural changes throughout life
Embryology – study of developmental changes of the body before birth
Specialized Branches of Anatomy Pathological anatomy – study of
structural changes caused by disease Radiographic anatomy – study of
internal structures visualized by specialized scanning procedures such as X-ray, MRI, and CT scans
Molecular biology – study of anatomical structures at a subcellular level
Physiology
Considers the operation of specific organ systems
Renal – kidney functionNeurophysiology – workings of the nervous systemCardiovascular – operation of the heart and blood vessels
Focuses on the functions of the body, often at the cellular or molecular level
Physiology
Understanding physiology also requires a knowledge of physics, which explains electrical currentsblood pressurethe way muscle uses bone for
movement
Principle of Complementarity Function
always reflects structure
What a structure can do depends on its specific form The human heart
Levels of Structural Organization Chemical – atoms combined to form
molecules Cellular – cells are made of molecules Tissue – consists of similar types of cells Organ – made up of different types of
tissues Organ system – consists of different
organs that work closely together Organismal – made up of the organ
systems
1
2
45
6
3
Smooth muscle cellMolecules
Atoms
Smoothmuscletissue
Epithelialtissue
Heart
Bloodvessels
Smoothmuscletissue
Connectivetissue
Bloodvessel(organ)
Cardiovascularsystem
Cellular levelCells are made up ofmolecules.
Tissue levelTissues consist ofsimilar types of cells.
Organ levelOrgans are made upof different typesof tissues.
Organ system levelOrgan systems consist ofdifferent organs thatwork together closely.
Organismal levelThe human organismis made up of manyorgan systems.
Chemical levelAtoms combine toform molecules.
Levels of Structural Organization
Figure 1.1
1
Molecules
Atoms
Chemical levelAtoms combine toform molecules.
Figure 1.1
1. Atoms combine to form molecules
1
2
Smooth muscle cellMolecules
AtomsCellular levelCells are made up ofmolecules.
Chemical levelAtoms combine toform molecules.
2.Molecules combine to form cells
Figure 1.1
1
2
3
Smooth muscle cellMolecules
Atoms
Smoothmuscletissue
Cellular levelCells are made up ofmolecules.
Tissue levelTissues consist ofsimilar types of cells.
Chemical levelAtoms combine toform molecules.
3.Cells get together to form tissues
Figure 1.1
1
2
4
3
Smooth muscle cellMolecules
Atoms
Smoothmuscletissue
Epithelialtissue
Smoothmuscletissue
Connectivetissue
Bloodvessel(organ)
Cellular levelCells are made up ofmolecules.
Tissue levelTissues consist ofsimilar types of cells.
Organ levelOrgans are made upof different typesof tissues.
Chemical levelAtoms combine toform molecules.
4. Tissues form organs
Figure 1.1
1
2
4
5
3
Smooth muscle cellMolecules
Atoms
Smoothmuscletissue
Epithelialtissue
Heart
Bloodvessels
Smoothmuscletissue
Connectivetissue
Bloodvessel(organ)
Cardiovascularsystem
Cellular levelCells are made up ofmolecules.
Tissue levelTissues consist ofsimilar types of cells.
Organ levelOrgans are made upof different typesof tissues.
Organ system levelOrgan systems consist ofdifferent organs thatwork together closely.
Chemical levelAtoms combine toform molecules.5. Groups of
organs make a system
Figure 1.1
1
2
4
5
6
3
Smooth muscle cellMolecules
Atoms
Smoothmuscletissue
Epithelialtissue
Heart
Bloodvessels
Smoothmuscletissue
Connectivetissue
Bloodvessel(organ)
Cardiovascularsystem
Cellular levelCells are made up ofmolecules.
Tissue levelTissues consist ofsimilar types of cells.
Organ levelOrgans are made upof different typesof tissues.
Organ system levelOrgan systems consist ofdifferent organs thatwork together closely.
Organismal levelThe human organismis made up of manyorgan systems.
Chemical levelAtoms combine toform molecules.
Figure 1.1
6. The entire organism
Integumentary System
Forms the external body covering
Composed of the skin, sweat glands, oil glands, hair, and nails
Protects deep tissues from injury and synthesizes vitamin D
Figure 1.3a
Skeletal System Composed of bone,
cartilage, and ligaments
Protects and supports body organs
Provides the framework for muscles
Site of blood cell formation
Stores mineralsFigure 1.3b
Muscular System
Composed of muscles and tendons
Movement and facial expression
Maintains posture Produces heat
Figure 1.3c
Nervous System
Composed of the brain, spinal column, and nerves
Is the fast-acting control system of the body
Responds to stimuli by activating muscles and glands
Figure 1.3d
Cardiovascular System
Composed of the heart and blood vessels
The heart pumps blood
The blood vessels transport blood throughout the body
Figure 1.3f
Lymphatic System
Composed of red bone marrow, thymus, spleen, lymph nodes, and lymphatic vessels
Picks up fluid leaked from blood vessels and returns it to blood
Disposes of debris in the lymphatic stream
Home to white blood cells involved with immunity
Figure 1.3g
Respiratory System
Composed of the nasal cavity, pharynx, trachea, bronchi, and lungs
Keeps blood supplied with oxygen and removes carbon dioxide
Figure 1.3h
Digestive System Composed of the oral
cavity, esophagus, stomach, small intestine, large intestine, rectum, anus, and liver
Breaks down food into small units that enter the blood
Eliminates indigestible food as feces
Figure 1.3i
Urinary System
Composed of kidneys, ureters, urinary bladder, and urethra
Eliminates nitrogenous wastes from the body
Regulates water, electrolyte, and pH balance of the blood
Figure 1.3j
Male Reproductive System Composed of prostate
gland, penis, testes, scrotum, and ductus deferens
Main function is the production of offspring
Testes produce sperm and male sex hormones
Ducts and glands deliver sperm to the female reproductive tract
Figure 1.3k
Female Reproductive System Composed of mammary
glands, ovaries, uterine tubes, uterus, and vagina
Main function is to produce of offspring
Ovaries produce eggs and female sex hormones
Remaining structures serve as sites for fertilization and development of the fetus
Mammary glands produce milk to nourish the newborn
Figure 1.3l
Organ Systems Interrelationships The integumentary system protects
the body from the external environment
Digestive and respiratory systems, in contact with the external environment, take in nutrients and oxygen
Organ Systems Interrelationships Nutrients and
oxygen are distributed by the blood
Metabolic wastes are eliminated by the urinary and respiratory systems
Figure 1.2
Figure 1.2
Necessary Life Functions
Maintaining boundaries – the internal environment remains distinct from the external environmentCellular level – accomplished by plasma
membranesOrganismal level – accomplished by the
skin Movement – locomotion, propulsion
(peristalsis), and contractility
Necessary Life Functions Responsiveness – ability to sense changes
in the environment and respond to them Digestion – breakdown of food Metabolism – all the chemical reactions that
occur in the body Excretion – removal of wastes from the body
Necessary Life Functions
Reproduction – cellular and organismal levels Cellular – an
original cell divides and produces two identical daughter cells
Organismal – sperm and egg unite to make a whole new person
Growth – increase in size of a body part or of the organism
egg
sperm
Survival Needs Nutrients – needed for energy and cell
building Oxygen – necessary for metabolic
reactions Water – provides the necessary
environment for chemical reactions Normal body temperature – necessary for
chemical reactions to occur at life-sustaining rates
Atmospheric pressure – required for proper breathing and gas exchange in the lungs
Homeostasis Homeostasis – ability to
maintain a relatively stable internal environment in an ever-changing outside world
The internal environment of the body is in a dynamic state of equilibrium
Chemical, thermal (temperature), and neural (nerve) factors interact to maintain homeostasis
Homeostatic Control Mechanisms Variables produce a change in the
body The three interdependent
components of control mechanisms:Receptor – monitors the environments
and responds to changes (stimuli)Control center – determines the set
point at which the variable is maintainedEffector – provides the means to
respond to stimuli
Homeostatic Control Mechanisms
Figure 1.4
Change detected by receptor
Stimulus: Produces changein variable
Input:Informationsent along afferentpathway to
Receptor (sensor) Effector
Controlcenter
Variable (in homeostasis)
Response ofeffector feedsback toinfluencemagnitude ofstimulus andreturns variableto homeostasis
Output:Information sentalong efferentpathway to
Imbalance
Imbalance
2
34
5
1
Homeostatic Control Mechanisms
Figure 1.4
Variable (in homeostasis)
Homeostatic Control Mechanisms
Figure 1.4
Stimulus: Produces changein variable
Variable (in homeostasis)
Imbalance
Imbalance
1
Homeostatic Control Mechanisms
Figure 1.4
Change detected by receptor
Stimulus: Produces changein variable
Receptor (sensor)
Variable (in homeostasis)
Imbalance
Imbalance
2
1
Homeostatic Control Mechanisms
Figure 1.4
Change detected by receptor
Stimulus: Produces changein variable
Input:Informationsent along afferentpathway to
Receptor (sensor)
Controlcenter
Variable (in homeostasis)
Imbalance
Imbalance
2
3
1
Homeostatic Control Mechanisms
Figure 1.4
Change detected by receptor
Stimulus: Produces changein variable
Input:Informationsent along afferentpathway to
Receptor (sensor) Effector
Controlcenter
Variable (in homeostasis)
Output:Information sentalong efferentpathway to
Imbalance
Imbalance
2
34
1
Homeostatic Control Mechanisms
Figure 1.4
Change detected by receptor
Stimulus: Produces changein variable
Input:Informationsent along afferentpathway to
Receptor (sensor) Effector
Controlcenter
Variable (in homeostasis)
Response ofeffector feedsback toinfluencemagnitude ofstimulus andreturns variableto homeostasis
Output:Information sentalong efferentpathway to
2
34
5
1
Negative Feedback
In negative feedback systems, the output shuts off the original stimulus
Example: Regulation of room temperature
Figure 1.5
Signalwire turnsheater on
Signalwire turnsheater off
Response;temperaturerises
Response;temperaturedrops
Stimulus: rising roomtemperature
Stimulus: dropping roomtemperature
Balance
Effector(heater)
Effector(heater)
Setpoint
Control center(thermostat)
Heateroff
Setpoint
Receptor-sensor(thermometer inThermostat)
Control center(thermostat)
Heateron
Imbalance
Imbalance
Receptor-sensor(thermometer inThermostat)
Figure 1.5
Balance
Figure 1.5
Stimulus: rising roomtemperature
Balance
Imbalance
Imbalance
Figure 1.5
Stimulus: rising roomtemperature
Balance
Imbalance
Imbalance
Receptor-sensor(thermometerIn thermostat)
Setpoint
Figure 1.5
Stimulus: rising roomtemperature
Balance
Imbalance
Imbalance
Receptor-sensor(thermometerIn thermostat)
Setpoint
Control center(thermostat)
Figure 1.5
Signalwire turnsheater off
Stimulus: rising roomtemperature
Balance
Effector(heater)
Stimulus: dropping roomtemperature
Imbalance
Imbalance
Receptor-sensor(thermometerIn thermostat)
Setpoint
Control center(thermostat)
Heateroff
Figure 1.5
Signalwire turnsheater off
Response;temperaturedrops
Stimulus: rising roomtemperature
Balance
Effector(heater)
Stimulus: dropping roomtemperature
Receptor-sensor(thermometerIn thermostat)
Setpoint
Control center(thermostat)
Heateroff
Figure 1.5
Stimulus: dropping roomtemperature
Balance
Imbalance
Imbalance
Figure 1.5
Stimulus: dropping roomtemperature
Balance
Setpoint
Receptor-sensor(thermometer inThermostat)
Imbalance
Imbalance
Figure 1.5
Stimulus: dropping roomtemperature
Balance
Setpoint
Receptor-sensor(thermometer inThermostat)
Control center(thermostat)
Imbalance
Imbalance
Figure 1.5
Signalwire turnsheater on
Stimulus: dropping roomtemperature
Balance
Effector(heater)
Setpoint
Receptor-sensor(thermometer inThermostat)
Control center(thermostat)
Heateron
Imbalance
Imbalance
Figure 1.5
Signalwire turnsheater on
Response;temperaturerises
Stimulus: dropping roomtemperature
Balance
Effector(heater)
Setpoint
Receptor-sensor(thermometer inThermostat)
Control center(thermostat)
Heateron
Figure 1.5
Signalwire turnsheater on
Signalwire turnsheater off
Response;temperaturerises
Response;temperaturedrops
Stimulus: rising roomtemperature
Stimulus: dropping roomtemperature
Balance
Effector(heater)
Effector(heater)
Setpoint
Control center(thermostat)
Heateroff
Setpoint
Receptor-sensor(thermometer inThermostat)
Control center(thermostat)
Heateron
Imbalance
Imbalance
Receptor-sensor(thermometer inThermostat)
Positive Feedback In positive feedback
systems, the output enhances or exaggerates the original stimulus
Example: Regulation of blood clotting
Figure 1.6
Figure 1.6
Releasedchemicalsattract moreplatelets
Clotting occursas platelets adhere to site and releasechemicals
Break or tear inblood vessel wall
Feedback cycleinitiated
Feedbackcycle endsafter clotseals break
Clotting proceeds; newly formingclot grows
2
1
34
Figure 1.6
Break or tear inblood vessel wall
Feedback cycleinitiated
1
Figure 1.6
Clotting occursas platelets adhere to site and releasechemicals
Break or tear inblood vessel wall
Feedback cycleinitiated
2
1
Figure 1.6
Releasedchemicalsattract moreplatelets
Clotting occursas platelets adhere to site and releasechemicals
Break or tear inblood vessel wall
Feedback cycleinitiated
2
1
3
Figure 1.6
Releasedchemicalsattract moreplatelets
Clotting occursas platelets adhere to site and releasechemicals
Break or tear inblood vessel wall
Feedback cycleinitiated
Clotting proceeds; newly formingclot grows
2
1
34
Figure 1.6
Releasedchemicalsattract moreplatelets
Clotting occursas platelets adhere to site and releasechemicals
Break or tear inblood vessel wall
Feedback cycleinitiated
Feedbackcycle endsafter clotseals break
Clotting proceeds; newly formingclot grows
2
1
34
Homeostatic Imbalance
Disturbance of homeostasis or the body’s normal equilibrium
Overwhelming the usual negative feedback mechanisms allows destructive positive feedback mechanisms to take over
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