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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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Cardiovascular
system
Organelle Molecule Atoms
Chemical level
Cellular level
Tissue level
Tissues consist of similar
types of cells.
Organ level
Organs are made up of different types
of tissues.
Organ system level
Organ systems consist of different
organs that work together closely.
Organismal level
The human organism is made up
of many organ systems.
Smooth muscle cell
Smooth muscle tissue
Connective tissue
Blood vessel (organ)
Heart
Blood
vessels
Epithelial
tissue
Smooth muscle tissue
1
2
3
4
5 6
Figure 1.1
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Survival Needs
1. Nutrients
• Chemicals for energy and cell building
• Carbohydrates, fats, proteins, minerals,
vitamins
2. Oxygen
• Essential for energy release (ATP
production)
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Survival Needs
3. Water
• Most abundant chemical in the body
• Site of chemical reactions
4. Normal body temperature
• Affects rate of chemical reactions
5. Appropriate atmospheric pressure
• For adequate breathing and gas exchange in the lungs
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Homeostasis
• Definition: Maintenance of a relatively stable
internal environment despite continuous
outside changes
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Components of a Homeostatic Control
Mechanism
1. Receptor (sensor)
• Monitors the environment
• Senses stimuli
2. Control center
• Receives input from receptor
• Determines the set point at which the variable is
maintained
• Determines appropriate response
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Components of a Control Mechanism
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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Stimulus
produces change in variable.
Receptor
detects change.
Input: Information sent along afferent pathway to control center.
Output:
Information sent along efferent pathway to effector.
Response
of effector feeds back to reduce the effect of stimulus and returns variable to homeostatic level.
Receptor Effector
Control
Center
BALANCE
Afferent
pathway
Efferent
pathway
1
2
3 4
5
Figure 1.4
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Negative Feedback
• The response reduces or shuts off the original
stimulus
• Example:
• Regulation of body temperature
Copyright © 2010 Pearson Education, Inc. Figure 1.5
Sweat glands activated
Shivering
begins
Stimulus
Body temperature
rises BALANCE
Information sent
along the afferent
pathway to control
center
Information sent
along the afferent
pathway to control
center
Afferent
pathway
Afferent
pathway
Efferent
pathway
Efferent
pathway
Information sent
along the efferent
pathway to
effectors
Information sent
along the efferent
pathway to effectors
Stimulus
Body temperature falls
Receptors
Temperature-sensitive
cells in skin and brain
Receptors
Temperature-sensitive
cells in skin and brain
Effectors
Sweat glands
Effectors
Skeletal muscles
Control Center
(thermoregulatory
center in brain)
Control Center
(thermoregulatory
center in brain)
Response
Evaporation of sweat
Body temperature falls;
stimulus ends
Response
Body temperature rises;
stimulus ends
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Positive Feedback
• The response enhances or exaggerates the
original stimulus
• Rare in biological systems
• 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. Figure 1.5
Cervical
(a) Anterior/Ventral
Pubic
Orbital Nasal Oral
Thoracic
Axillary
Sternal
Abdominal
Umbilical
Pelvic
Inguinal
Upper limb
Acromial Brachial (arm) Antecubital Antebrachial
(forearm) Carpal (wrist)
Digital
Lower limb
Coxal (hip) Femoral (thigh) Patellar Crural (leg) Fibular
Tarsal (ankle) Thorax
Abdomen Back (Dorsum)
Copyright © 2010 Pearson Education, Inc. Figure 1.5
Cervical
Back (dorsal)
(b) Posterior/Dorsal
Scapular Vertebral Lumbar Sacral Gluteal
Upper limb
Acromial Brachial (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
Vertebral
column
Spinal cord
Subcutaneous fat layer Body wall
Rectum Intestines Left and
right lungs
Liver Heart
Stomach
Spleen
Arm
(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
Cranial
cavity
Dorsal
body
cavity
Vertebral
cavity
Cranial
cavity
Vertebral
cavity
Abdomino-
pelvic
cavity
Ventral body
cavity
(thoracic and
abdominopelvic
cavities)
Abdominal cavity
(contains digestive
viscera)
Diaphragm
Pelvic cavity
(contains urinary
bladder, reproductive
organs, and rectum)
Thoracic
Cavity
(a) Lateral view (b) Anterior view
Dorsal body cavity
Ventral 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
Cranial
cavity
Dorsal
body
cavity
Vertebral
cavity
Cranial
cavity
Vertebral
cavity
Abdomino-
pelvic
cavity
Ventral body
cavity
Abdominal cavity
Diaphragm
Pelvic cavity
Thoracic
cavity
(a) Lateral view (b) Anterior view
Dorsal body cavity
Ventral body cavity
Copyright © 2010 Pearson Education, Inc. Figure 1.12
Epigastric
region
Umbilical
region
Right
lumbar
region
Left
lumbar
region
Right
hypochondriac
region
Left
hypochondriac
region
Hypogastric
(pubic)
region
Right iliac
(inguinal)
region
Left iliac
(inguinal)
region
Liver
Gallbladder
Ascending colon of
large intestine
Small intestine
Appendix
Cecum
Diaphragm
Stomach
Descending colon
of large intestine
Transverse colon
of large intestine
Initial part of
sigmoid colon
Urinary bladder
(a) Nine regions delineated by four planes (b) Anterior view of the nine regions showing the superficial organs