Post on 31-Dec-2015
The Human Body: Anatomical Regions,
Directions, Body Cavities, and Homeostasis
Credit: Carlos J Bidot Author 2006Revised 2010
Overview of Anatomy and Physiology
• AnatomyAnatomy – the study of the structure of body parts and their relationships to one another– Gross or macroscopic– Microscopic– Developmental
• PhysiologyPhysiology – the study of the function of the body’s structural machinery
Gross Anatomy
• RegionalRegional – all structures in one part of the body (such as the abdomen or leg)
• SystemicSystemic – gross anatomy of the body studied by system
• SurfaceSurface – study of internal structures as they relate to the overlying skin
Microscopic Anatomy
• CytologyCytology – study of the cell
• HistologyHistology – study of tissues
Developmental Anatomy
• Traces structural changes throughout life
• EmbryologyEmbryology – study of developmental changes of the body before birth
Specialized Branches of Anatomy
• Pathological anatomyPathological anatomy – study of structural changes caused by disease
• Radiographic anatomyRadiographic anatomy – study of internal structures visualized by X ray
• Molecular biologyMolecular biology – study of anatomical structures at a sub-cellular level
Physiology
• Considers the operation of specific Considers the operation of specific organ systemsorgan systems– Renal – kidney function– Neurophysiology – workings of the nervous
system– Cardiovascular – operation of the heart and
blood vessels
• Focuses on the functions of the Focuses on the functions of the body, often at the cellular or body, often at the cellular or molecular levelmolecular level
Chemical levelAtoms combine to form molecules
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Cellular levelCells are made up of molecules
Tissue levelTissues consist of similar types of cells
5 Organ system levelOrgan systems consist of different organs that work together closely
Organ levelOrgans are made up of different types of tissues
6 Organismal levelThe human organism is made up of many organ systems
Atoms
Molecules
Smooth muscle cell
Smooth muscle tissue
Connective tissue
Smooth muscle tissue
Epithelial tissue
Blood vessel (organ)
Heart
Blood vessels
Cardiovascular system
Levels of Structural Organization
Figure 1.1
Levels of Structural Organization
(*VERY important*)• ChemicalChemical – atoms combined to form molecules
• CellularCellular – cells are made of molecules• TissueTissue – consists of similar types of cells• OrganOrgan – made up of different types of
tissues• Organ systemOrgan system – consists of different
organs that work closely together• OrganismOrganism – made up of the organ
systems
Homeostasis
External environment – keeps changingInternal environment - remains stable. How?
Body has “Homeostatic Mechanisms”
Imagine one day is very cold out, while the next day is very hot.
What effect does that have on your body temperature?
Homeostasis
• HomeostasisHomeostasis is the 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 equilibriuma dynamic state of equilibrium
• Chemical, thermal, and neural factors interact to maintain homeostasis
Feedback Loops
• The beginning of a reflex pathway is a disturbance in a controlled parameter called a stimulus
• The stimulus is detected by a sensor (receptor)– continuously monitoring the environment– when a change is detected, it sends out a
signal
• The signal travels from the receptor to the control (integrating) center
Feedback Loops• The control center evaluates the incoming
signal, compares it to the homeostatic setpoint, and decides on the appropriate response
• The control center sends out a signal to the effector
• The effector is a cell or tissue that carries out the appropriate response to bring the parameter back to within normal limits (setpoint)
Types of Feedback
• Negative feedback– Most common– The effector removes the cause of
imbalance– Ex. Body temperature, blood pH
• Positive feedback– The effector reinforces the stimulus
(does not stop it)– Ex. Blood clotting, labor
Anatomical Position
• Body erect • Feet slightly apart• Palms facing
forward • Thumbs point
away from body
Figure 1.7a
Directional Terms
• Superior and inferiorSuperior and inferior – toward and away from the head, respectively
• Anterior and posteriorAnterior and posterior – toward the front and back of the body
• Medial, lateral, and intermediateMedial, lateral, and intermediate – toward the midline, away from the midline, and between a more medial and lateral structure
Directional Terms
• Proximal and distalProximal and distal – closer to and farther from the origin of the body
• Superficial and deepSuperficial and deep – toward and away from the body surface
Directional Terms Table 1.1
Directional Terms Table 1.1
Regional Terms: Anterior View
• AxialAxial – head, neck, and trunk
• AppendiculAppendicularar – appendages or limbs
• Specific Specific regional regional terminologyterminology
Figure 1.7a
Regional Terms: Posterior View
Figure 1.7b
Activity!
• https://www.wisc-online.com/learn/natural-science/life-science/ap15305/anatomical-terminology-relative-position
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Anatomical Locations• Abdominal: abdominal region• Acromial: the point of the shoulder• Antebrachial: forearm• Antecubital: anterior surface of the
elbow• Axillary: armpit• Brachial: upper arm• Buccal: cheek of the face• Calcaneal: heel of the foot• Carpal: wrist• Cephalic: head
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Anatomical Locations• Cervical: neck• Deltoid: round part of the shoulder• Digital: fingers and toes• Dorsum: back • Femoral: thigh• Frontal: forehead• Gluteal: buttocks• Hallux: big toe• Inguinal: groin• Lumbar: lower back• Mammary: breast
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Anatomical Locations• Mental: chin• Nasal: Nose• Occipital: base of the skull• Olecranal: elbow• Oral: mouth• Orbital: bony eye socket• Otic: ear• Palmar: palm of hand• Patellar: Kneecap• Pedal: Foot
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Anatomical Locations• Pelvic: pelvis region• Perineal: area between anus and
external genitals• Plantar: sole of foot• Pollex: thumb• Popliteal: behind the knee• Pubic: genital region• Sacral: lower back between the hips• Scapular: shoulder blade• Tarsal: ankle• Thoracic: chest• Vertebral: spine
Body Planes• SagittalSagittal – divides the body into right
and left parts• Midsagittal or medialMidsagittal or medial – sagittal
plane that lies on the midline• Frontal or coronalFrontal or coronal – divides the
body into anterior and posterior parts• Transverse or horizontalTransverse or horizontal (cross
section) – divides the body into superior and inferior parts
• Oblique sectionOblique section – cuts made diagonally
Body Planes Figure 1.8
Anatomical Variability
• Humans vary slightly in both Humans vary slightly in both external and internal anatomyexternal and internal anatomy
• Over 90% of all anatomical structures match textbook descriptions, but:– Nerves or blood vessels may be
somewhat out of place– Small muscles may be missing
• Extreme anatomical variations Extreme anatomical variations are seldom seenare seldom seen
Body Cavities
Figure 1.9a
Body Cavities• Dorsal cavityDorsal cavity protects the nervous
system, and is divided into two subdivisions– Cranial cavity is within the skull and
encases the brain– Vertebral cavity runs within the vertebral
column and encases the spinal cord• Ventral cavityVentral cavity houses the internal organs
(viscera), and is divided into two subdivisions: - Thoracic and Abdominopelvic cavities
Body CavitiesFigure 1.9b
Body Cavities
• Thoracic cavityThoracic cavity is subdivided into pleural cavities, the mediastinum, and the pericardial cavity– Pleural cavities – each houses a lung– Mediastinum – contains the
pericardial cavity, and surrounds the remaining thoracic organs
– Pericardial cavity – encloses the heart
Body Cavities• The abdominopelvic cavity is
separated from the superior thoracic cavity by the dome-shaped diaphragm
• It is composed of two subdivisions– Abdominal cavity – contains the
stomach, intestines, spleen, liver, and other organs
– Pelvic cavity – lies within the pelvis and contains the bladder, reproductive organs, and rectum
Ventral Body Cavity Membranes
• Parietal serosaParietal serosa lines internal body walls
• Visceral serosaVisceral serosa covers the internal organs
• Serous fluid separates the serosae (A serous membrane, especially one that lines the pericardial, pleural, and peritoneal cavities, enclosing their contents)
Ventral Body Cavity Membranes
Figure 1.10a
Ventral Body Cavity Membranes
Figure 1.10b
Other Body Cavities
• Oral and digestiveOral and digestive – mouth and cavities of the digestive organs
• NasalNasal –located within and posterior to the nose
• OrbitalOrbital – house the eyes• Middle earMiddle ear – contain bones (ossicles)
that transmit sound vibrations• SynovialSynovial – joint cavities
Abdominopelvic Regions
• Umbilical• Epigastric• Hypogastric• Right and left
iliac or inguinal• Right and left
lumbar• Right and left
hypochondriacFigure 1.11a
Organs of the Abdominopelvic Regions
Figure 1.11b
Abdominopelvic Quadrants
• Right upper (RUQ)
• Left upper (LUQ)
• Right lower (RLQ)
• Left lower (LLQ)
Figure 1.12