Download The Human Body: An Orientation

The Human Body: An
Orientation
Department of Applied Science
King Saud University/ Community College
By: YASSIN ABOBAKER A.
The Human Body: An Orientation
Outline
Survival Needs
Language of Anatomy
Anatomical Position
Regional Terms
Directional Terms
Body Planes and Sections
Body Cavities
Homeostasis
Survival Needs
• Nutrients
– Taken in through the diet
– Macronutrients
• Carbohydrates – energy
• Proteins – energy; building cell structures
• Lipids – stored energy; building cell
structures; cushioning
– Micronutrients
• Vitamins and minerals – chemical reactions;
oxygen transport
• Oxygen
– Necessary for the production of energy
– C6H12O6 +O2  CO2 + H2O + energy
• Water
– 60 – 80 % of body weight
– Necessary for
• Secretions, excretions
• Transport of substances
• Chemical reactions
• Body Temperature
– Maintained at about 37 degrees C
– Necessary for metabolism
• Higher and enzymes breakdown
• Lower and reactions slow and then stop
• Atmospheric Pressure
– Force on the surface of the body due to the
weight of air
– Necessary for breathing
Language of Anatomy
• Special language created to give precise information
about the location of body structures
• Latin and Greek roots, prefixes and suffixes
• Eponyms
– Many are being replaced with more precise,
descriptive terms
– Islets of Langerhans – pancreatic islets
Anatomical Position
• Reference position
• Body erect with arms at sides and palms forward.
• Head & feet pointing forward.
• Bilateral symmetry: is a term meaning that right & left sides of
body are mirror images.
1) Ipsilateral structures: are on the same side of the body in
anatomical position.
2) Contralateral structures: are on opposite sides of the body in
anatomical position.
• Regional Terms –
– Anterior Body Landmarks
– Posterior Body Landmarks
Directional Terms
• They are Terms used in describing body structure
• Used to explain exactly where one body structure is in relation to
another
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•
•
•
•
•
•
•
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– Assume anatomical position
Superior (cranial): means “toward the head”
Inferior (caudal): toward the feet
Anterior (ventral): in front of
Posterior (dorsal): in back of
Medial: toward the midline of the body
Lateral: toward the side of the body
Proximal: nearest the trunk of the body
Distal: away from the trunk
Superficial: nearer the surface
Deep: farther away from the body surface
Body Planes and Sections
• Planes and Sections
– Plane – imaginary line separating body parts
– Section – cut along the plane (named for the
plane)
• Transverse plane
– Divides the body into superior and inferior
sections
– Transverse section or cross section
• Frontal (Coronal) plane
– Divides the body into anterior and posterior
sections
• Sagittal plane
– Divides the body into unequal right and left
sections
• Midsagittal plane
– Divides the body into equal right and left sections
Body Cavities
• The body can be divided into an:
1) Appendicular portion (upper and lower
limbs or extremities).
2) Axial portion (head, neck, and trunk)
• The body is not a solid structure, it contains
two cavities:
1) Ventral cavity.
2) Dorsal cavity.
• Organs within
viscera.
these
cavities
are
called
• Dorsal Cavity
– Cranial – brain
– Spinal – spinal cord
• Ventral Cavity
– Thoracic Cavity
– Abdominopelvic Cavity
– Separated by the diaphragm
Body Cavities
• Protect the organs
• Permit the organs to change in size and
shape
– Heart contraction
– Stomach distend with food
• Two major cavities
– Dorsal
– Ventral
• Thoracic Cavity
– Pleural – lungs
– Mediastinum – esophagus, trachea, heart
– Pericardial – heart only
• Abdominopelvic Cavity
– Abdominal – digestive viscera
– Pelvic – bladder, reproductive organs
Cavities in the Head w/ Viscera
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•
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•
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Sinus – air filled cavities in cranial bones
Orbital cavity - eyeball
Nasal cavity – air and mucus
Oral cavity – teeth and tongue
Middle ear cavity – connects ear with atmospheric
pressure via pharynx
Abdominopelvic Cavity
• Quadrants – 4
– Right and left upper quadrant
– Right and left lower quadrant
• Regions – 9
– Right and left hypochondriac
– Right and left lumbar
– Right and left iliac
– Epigastric
– Umbilical
– Hypogastric
•
Body Regions
1.
The abdominal area can be divided into nine regions.
2.
Terms used to refer to various body regions.
Homeostasis
Homeo - sameness
Stasis - standing still
• Homeostasis
– Ability of the body to maintain relatively
stable internal environment regardless of
external environment
• Dynamic changing state which operates
within a range not a set point
– Body temperature 37º F
– Homeostasis range
• 36.5º C – 37.5º C
Homeostatic Control
Mechanisms
• Nervous and Endocrine system
– Nervous system
• Electrical signals - impulses
– Endocrine system
• Hormones transported in blood to target cells
• Receptor
– Monitors the environment
– Detects changes
• Stimuli – changes in the environment
• Control Center
– Integration center
– Determines the set point within the range
– Analyzes the information
– Determines the response
• Effector
– Provides the response
• Muscles contract or relax
• Glands secrete or stop secreting
Feedback mechanisms
• Homeostasis maintained through either:
– Negative feedback mechanisms
• opposes response to stimulus
– Positive feedback mechanisms
• enhances response to stimulus
Negative Feedback
Mechanisms
• Opposes (limits the intensity) or eliminates the
original stimulus
• Negative means that the variable changes in a
direction opposite to the initial change
• Negative feedback maintains body functions within a
range
• Most homeostatic mechanisms in the body involved
negative feedback
• Mechanisms ignore minor variations but maintain
homeostasis within a range
Positive Feedback
Mechanisms
• The response enhances or exaggerates the original
stimulus
• Positive means that the change occurs in the
direction of the original stimulus
• Rarely used to promote homeostasis
• Examples
– Childbirth – pressure receptors; effector muscles
of uterus; contraction to push baby through birth
canal
– Blood clotting – increase in number of platelets
sticking to the broken blood vessel
Homeostatic imbalance
• Most diseases and/or disorders result from
homeostatic imbalance
• With aging:
– body organs and control systems become less
efficient
– internal environment becomes less and less
stable
– greater risk of illness/injury
Thank you for listening
Yassin Abobaker A.