pyright © 2010 Pearson Education, Inc. THE HUMAN BODY: AN ORIENTATION CH. 1A
Dec 26, 2015
Copyright © 2010 Pearson Education, Inc.
THE HUMAN BODY: AN ORIENTATION CH. 1A
Copyright © 2010 Pearson Education, Inc.
Overview of Anatomy and Physiology
• Anatomy: Study of the structure/parts
• Physiology: The study of function at many levels
• Function always reflects structure; What a structure can do depends on its specific form
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Levels of Structural Organization
• Chemical: atoms and molecules
• Cellular: cells and their organelles
• Tissue: groups of similar cells
• Organ: contains two or more types of tissues
• Organ system: organs that work closely together
• Organismal: all organ systems
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Cardiovascularsystem
OrganelleMoleculeAtoms
Chemical level Cellular level
Tissue levelTissues consist of similartypes of cells.
Organ levelOrgans are made up of different typesof tissues.
Organ system levelOrgan systems consist of differentorgans that work together closely.
Organismal levelThe human organism is made upof many organ systems.
Smooth muscle cell
Smooth muscle tissue
Connective tissue
Blood vessel (organ)
HeartBloodvessels
Epithelialtissue
Smooth muscle tissue
12
3
4
56
Figure 1.1
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Homeostasis
• Definition: Maintenance of a relatively stable internal environment despite continuous outside changes
• Homeostasis is maintained by homeostatic control mechanisms which involve at least three components: receptor, control center, effector
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Components of a Homeostatic Control Mechanism
1. Receptor (sensor)
• Monitors the environment and senses stimuli
2. Control center
• Receives input from receptor
• Determines the set point at which the variable is maintained
• Determines appropriate response
3. Effector
• Receives output from control center
• Provides the means to respond
• Response acts to reduce or enhance the stimulus (feedback)
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Stimulusproduceschange invariable.
Receptordetectschange.
Input: Informationsent along afferentpathway to controlcenter.
Output:Information sent alongefferent pathway toeffector.
Responseof effectorfeeds backto reducethe effect ofstimulusand returnsvariable tohomeostaticlevel.
Receptor Effector
ControlCenter
BALANCE
Afferentpathway
Efferentpathway
IMBALANCE
IMBALANCE
1
2
34
5
Figure 1.4
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Negative Feedback
•When the response of a control mechanism reduces or shuts off/stops the original stimulus, this is called negative feedback
• Example:
• Regulation of body temperature
Copyright © 2010 Pearson Education, Inc. Figure 1.5
Sweat glands activated
Shiveringbegins
StimulusBody temperaturerises BALANCE
Information sentalong the afferentpathway to controlcenter
Information sentalong the afferentpathway to controlcenter
Afferentpathway
Afferentpathway
Efferentpathway
Efferentpathway
Information sentalong the efferentpathway toeffectors
Information sentalong the efferentpathway to effectors
StimulusBody temperature falls
ReceptorsTemperature-sensitivecells in skin and brain
ReceptorsTemperature-sensitivecells in skin and brain
EffectorsSweat glands
EffectorsSkeletal muscles
Control Center(thermoregulatory
center in brain)
Control Center(thermoregulatory
center in brain)
ResponseEvaporation of sweatBody temperature falls;stimulus ends
ResponseBody temperature rises;stimulus ends
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Positive Feedback
•When the response of a control mechanism enhances or exaggerates the original stimulus, this is called positive feedback
• Example:
• Enhancement of labor contractions by oxytocin
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Anatomical Position
• Purpose:
• Standard anatomical body position:
• Body erect
• Feet slightly apart
• Palms facing forward
Copyright © 2010 Pearson Education, Inc. Table 1.1
Copyright © 2010 Pearson Education, Inc. Table 1.1
Copyright © 2010 Pearson Education, Inc. Table 1.1
Copyright © 2010 Pearson Education, Inc. Table 1.1
Copyright © 2010 Pearson Education, Inc. Table 1.1
Copyright © 2010 Pearson Education, Inc. Figure 1.5
Cervical
(a) Anterior/Ventral
Pubic
OrbitalNasalOral
ThoracicAxillary
SternalAbdominalUmbilicalPelvicInguinal
Upper limbAcromialBrachial (arm)AntecubitalAntebrachial (forearm)Carpal (wrist)
Digital
Lower limbCoxal (hip)Femoral (thigh)PatellarCrural (leg)Fibular
Tarsal (ankle)ThoraxAbdomenBack (Dorsum)
Copyright © 2010 Pearson Education, Inc. Figure 1.5
Cervical Back (dorsal)
(b) Posterior/Dorsal
Scapular Vertebral Lumbar Sacral Gluteal
Upper limb AcromialBrachial (arm) Olecranal
Digital
Femoral (thigh) Popliteal Sural (calf) Fibular
Calcaneal Plantar
Cephalic
Occipital (back of head)
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Body Planes and Sections
• Sagittal plane
• Divides body vertically into right and left parts
• Produces a sagittal section
• Midsagittal (median) plane
• Lies on midline
• Parasagittal plane
• Not on midline
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Body Planes
• Frontal (coronal) plane
• Divides body vertically into anterior and posterior parts
• Transverse (horizontal) plane
• Divides body horizontally into superior and inferior parts
• Produces a cross section
Copyright © 2010 Pearson Education, Inc. Figure 1.6
Transverse plane
Median (midsagittal) plane
Frontal plane
Liver
Spleen
Pancreas
Aorta
Vertebralcolumn
Spinal cord
Subcutaneous fat layerBody wall
Rectum IntestinesLeft andright lungs
Liver HeartStomach
SpleenArm
(a) Frontal section (through torso)
(b) Transverse section (through torso, inferior view)
(c) Median section (midsagittal)
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Body Cavities
• Two Large Cavities:
• Dorsal cavity encloses the CNS
• Two subdivisions:
• Cranial cavity
• Encases brain
• Vertebral cavity
• Encases spinal cord
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Body Cavities
• Ventral cavity
• Houses soft internal organs (viscera)
• Two subdivisions (separated by diaphragm):
• Thoracic cavity
• Abdominopelvic cavity
Copyright © 2010 Pearson Education, Inc. Figure 1.7
Cranialcavity
Dorsalbodycavity
Vertebralcavity
Cranialcavity
Vertebralcavity
Abdomino-pelviccavity
Ventral bodycavity(thoracic andabdominopelviccavities)
Abdominal cavity(contains digestiveviscera)
Diaphragm
Pelvic cavity(contains urinary bladder, reproductive organs, and rectum)
ThoracicCavity
(a) Lateral view (b) Anterior view
Dorsal body cavityVentral body cavity
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Ventral Body Cavities
• Thoracic cavity subdivisions:
• Two pleural cavities
• Each houses a lung
• Mediastinum
• Contains pericardial cavity
• Also contains the esophagus and aorta
• Pericardial cavity
• Encloses heart
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Ventral Body Cavities
• Abdominopelvic cavity subdivisions:
• Abdominal cavity
• Contains stomach, intestines, spleen, and liver
• Pelvic cavity
• Contains urinary bladder, reproductive organs, and rectum
Copyright © 2010 Pearson Education, Inc. Figure 1.7
Cranialcavity
Dorsalbodycavity
Vertebralcavity
Cranialcavity
Vertebralcavity
Abdomino-pelviccavity
Ventral bodycavity
Abdominal cavity
Diaphragm
Pelvic cavity
Thoraciccavity
(a) Lateral view (b) Anterior view
Dorsal body cavityVentral body cavity
Copyright © 2010 Pearson Education, Inc. Figure 1.12
Epigastricregion
Umbilicalregion
Rightlumbarregion
Leftlumbarregion
Righthypochondriac
region
Lefthypochondriac
region
Hypogastric(pubic)region
Right iliac(inguinal)
region
Left iliac(inguinal)
region
Liver
Gallbladder
Ascending colon oflarge intestine
Small intestine
Appendix
Cecum
Diaphragm
Stomach
Descending colonof large intestine
Transverse colonof large intestine
Initial part ofsigmoid colon
Urinary bladder
(a) Nine regions delineated by four planes (b) Anterior view of the nine regions showing the superficial organs
Nine Abdominopelvic Regions