a.​Organization of the Human Body
1.1 Overview of Anatomy and Physiology
Human “Anatomy” (to cut apart): scientific study of the body’s structures and their
relationships to each other
●​ “To cut apart”
Areas of specializations
●​ Gross anatomy (macroscopic anatomy): study of larger structures – visible without aid
of magnification
○​ Can be manipulated, measured, weighed
●​ Microscopic anatomy: study of structures that can be observed only with a microscope
or other magnification
○​ Cytology – study of cells
○​ Histology – study of tissues
Approaches
●​ Regional anatomy: study of the interrelationships (how muscles, nerves, blood vessels
work together) of all the structures in a specific body region (i.e. abdomen)
●​ Systemic anatomy: study of the structures that make up a discrete body system –
group of structures that work together to perform a unique body function (i.e. all the
skeletal muscles)
Human Physiology: scientific study of how various structures of the body function and work
together
●​ Homeostasis: state of steady internal conditions maintained by living things
●​ Observation (with naked eye and microscope), manipulations, measurements
→ form and function are intimately related
1.2 Structural Organization of the Human Body
The Levels of Organization
●​ Subatomic particles
●​ Atom: smallest unit of pre substances (elements) – hydrogen, oxygen, etc. Atoms are
made up of subatomic particles (proton, electron, neutron)
○​ All matter in the universe is composed of one or more elements
●​ Molecule: two or more atoms
○​ Chemical building blocks of all body structures
○​ EX: water molecules, proteins, sugars
●​ Cell: smallest independently functioning unit of a living organism
○​ ALL living structurs of human anatomy contain cells, and ALMOST all functions
of human physiology are performed in cells/ initiated by cells (i.e. bacteria)
○​ They perform all functions of life
○​ Consists of flexible membranes that enclose cytoplasm – water-based cellular
fluid with organelles..
■​ Tissue: group of many similar cells work together for specific function
●​ Organ: anatomically distinct structure comepred of two or more
tissue types. Each organ performs one or more physiological
functions.
○​ Organ system: group of organs work together to perform
major junctions or meet physiological needs of the body
■​ Organism: living being that has a cellular structure
and that can independently perform all physiologic
functions necessary for life
Eleven (11) distinct organ systems
Integumentary System: (largest)
●​ Encloses internal body structures
●​ Site of sensory receptors
●​ Prevents drying out
●​ Potects from infection
●​ Regulates body temperature (sweat)
●​ Makes vitamin D when exposed to UV
light
Hair, skin, nails
Skeletal System:
●​ Supports and protects the body
●​ Enables movement (with muscular
system)
●​ Storage of stem cells (that develop
into blood cells)
●​ Storage of minerals (calcium)
●​ Storage of fats
Cartilage, bones, joints
Muscular System:
●​ Enables mouvement (with skeletal
system)
●​ Helps maintain body temperature
through shivering
●​ Human communication
●​ Stabilize body position
Skeletal muscles, tendons
Nervous System:
●​ Central and peripheral nervous
systems
●​ Detects and processes sensory
information
●​ Activates bodily responses
Brain, spinal cord, peripheral nerves
Endocrine System:
●​ Cells, tissues, and glands that secrete
hormones
●​ Hormones bind to receptors in target
cells and regulates bodily processes
○​ Pancreas beta cells: insulin
○​ Pituitary gland: growth
hormone
Cardiovascular System:
●​ Delivers oxygen and nutrients to
tissues via red blood cells
●​ Regulates acid-base balance
●​ Regulates body temperature
●​ Regulates water content
●​ Protects from infection
Heart, blood vessels
○​ Adrenal glands: stress
hormones
○​ Reproductive organs:
testosterone and estrogen
Lymphatic System:
●​ Supports function of circulatory
system by returning fluid and proteins
to blood
●​ Lymphocytes defends against
pathogens
Thymus, lymph nodes, spleen, lymphatic
vessels
Respiratory System:
●​ Removes carbon dioxide
●​ Delivers oxygen to blood
●​ Regulates acid-base balance
●​ Produces voice
Nasal passage, trachea, lungs
Digestive System:
●​ Processes food into chemical
nutrients for absorption
●​ Removes solid wastes from
undigested food
Stomach, liver, gallbladder, large/small
intestine
Unrinary System:
●​ Produces, stores, and eliminates urine
●​ Controls water balance
●​ Removes wastes from blood and
excretes them
●​ Regulates volume, chemical
composition, acid-base balance,
production of red blood cells
Kidneys, urinary bladder
Male Reproductive System
●​ Produce sex hormones and gametes
●​ Delivers gametes to female
Epididymis, testes
Female Reproductive System
●​ Produces sex hormones and gametes
●​ Supporst embryo/fetus until birth
●​ Produces milk for infant
Mammary glands, ovaries, uterus
b.​Functions of Life and Requirements for Life
1.3 Functions of Human Life
Organization
●​ Compartmentalization: separation of internal and external environments
○​ Cell plasma membranes and intracellular organelles
○​ Cells organized into tissues
○​ Lining of body cavities, blood vessles, digestive tract, etc.
○​ Integumentary system
●​ Structure and function are cerrelated at all levels of organization
Metabolism – sum of anabolic and ctabolic reactions
●​ Energy can neither be created nor destroyed
●​ Convert energy from one form into another
○​ Digest food to extract energy and use it to fuel many cellular activities
●​ Sum of anabolic and catabolic reactions that occur in the body
●​ Catabolism:
○​ Break complex molecules down into smaller subunits
○​ Releases energy (exergonic)
○​ Example: proteins broken down into amino acids
●​ Anabolism:
○​ Build complex molecules from smaller subunits from the food you eat
○​ Requires input of energy (endergonic)
○​ Energy is stored
○​ Example: amino acids are bonded together to form proteins
→ occur simultaneously
●​ Every cell in your body makes use of a chemical compound, adenosine triphsphate
(ATP), to store and release energy
Responsiveness
●​ Excitability
●​ Body can sense and respond to changes in both the external and internal environment
●​ EX: runners
○​ Sweat glands activities to regulate body temperature
○​ Motor neurons send nerve impulse to activated skeletal muscles
Movement
●​ Motions of body: in joints, organs, tissues and cells
●​ EX: runners
○​ Skeletal muscles contract to pull on bones and create movements
Development, growth, and reproduction
●​ Development: changes in body through life
●​ Differentiation: unspecialized to specialized cell
●​ Growth: increase in body size
○​ Size of cells
○​ # of cells
○​ Amount of extracellular material
●​ Renewal: replacement of cells (skin, lining of intestine…)
reproduction
●​ Merging of gametes from parent organisms (sperm and egg) to form a new organism
Maintenance of homeostasis
1.4 Requirements for Human Life
Oxygen
●​ Oxygen (needed for reactions that produce ATP) – aerobic respirations makes ATP
○​ Brain cells most sensitive to lack of oxygen
●​ Brain damage → 5 minutes without oxygen
●​ Death → 10 minutes
Nutrients
●​ Substances needed to sustain life
●​ Water: 70% of adult body mass; needed for all chemical reaction
○​ Regulate internal temperature and cushions, protects, and lubricates joints..
●​ Macronutrients: needed in large amounts
○​ “Energy-yielding” : carbohydrates and lipids
■​ Can survive without for several weeks
○​ “Body-building” : proteins
●​ Micronutrients: needed in small amounts (for certain chemical reactions)
○​ Vitamins
○​ Minerals
Temperature
●​ Narrow range: deaths from heat stroke or hypethermia (just below of above 37ºC)
●​ Outside normal range
○​ proteins/enzymes structure and/or function change
○​ Cheical reactions will halt
●​ Body can respond to short-term changes: sweating and shivering
○​ Sweat in humid environments is less effective since it cannot evaporate from skin
– body temp get very high
○​ Cold – red blood cells lose abilityt to give up oxygen → confusing, lethargy, loss
of consciousness, death
●​ Clinically-induced hypothermia: used during surgery to reduce metabolic demands on
organs like the heart (open heart surgery, cardiac arrest); less blood requiments =
reduce heart workload
Atmospheric Pressure
●​ Narrow range of atmospheric pressure
○​ Gases (N2, O2) in Earth’s atmosphere exert pressure on your body
○​ Keeps gases in your body fluids (N2) dissolved
○​ Allows for proper exchange of O2 and CO2 in respiratory system
○​ Decompression sickness (DCS) and altitude sickness
■​ Condition in which asses dissolved in the blood or tissues are no longer
dissolved = reduction in pressure on the body
●​ Affects divers and pilots
○​ “The bends” – joint pain
Homeostasis
1.5 Homeostasis
Definition: maintenance of stable internal environment: a set point (physiological value, EX:
body temp 37ºC) around which a normal range (restricted set of values that is optimally healthful
and stable fluctuates
●​ Body temp, pH concentrations of dissolved salts in interstitial fluids, blood pressure,
blood glucose levels, O2, and CO2…
Hemeodynamics
●​ Denamic control system
●​ Constant monitoring
●​ System of feedback controls
●​ Constant communication involving endocrine and nervous systems
Components of a Homeostatic Control System
1.​ Feedback loops
a.​ Sensor or receptor monitors value
b.​ Control centre compares value to normal range
c.​ Effector receives output from control centre and produces a
change to return the value to the normal range
d.​ Usually an afferent pathway to the control centre, and an
efferent pathway away from the control centre
●​
Negative feedback
○​ Mechanism that reverse a deviation from the set point
○​ maintain s body parameters within their normal range
○​ EX: when body temp exceed its normal range, it stmiulates cluster of brain cells –
“heat-loss centre”
■​ Blood vessels begin to dilate → more blood from the body core to flow to
the surface of the skin allowing the heat to radiate into the environment.
■​ As blood flow to the skin increases, sweat glands are activated to
increase their output. As the sweat evaporates from the skin surface into
the surrounding air, it takes heat with it.
■​ The depth of respiration increases, person may breathe through an open
mouth instead of through the nasal passageways. This further increases
heat loss from the lungs.
■​ (the breakdown of glycogen into glucose also increases metabolism and
heat production)
●​ Positive feedback
○​ Normal only when there is a definite end point
○​ EX: childbirth and body’s response to blood loss
2.​ Condition to be controlled within a narrow range
3.​ Stimulus that perturbs or creates an imbalance
Homeostasis is vital for health
→ imbalances can lead to disease or death
●​ Temporary imbalances can be corrected (altitude sickness, decompression sickness)
●​ Disease
○​ A pathological process that may or may not produce symptoms
■​ Symptoms are subjective changes in function
■​ Signs are objective changes in function
●​ Long-term imbalances can lead to chronic disease
○​ Type 2 diabetes
○​ Cardiovascular disease
○​ Cancer
Anatomical terminology
Anatomical Position
●​ Standing upright, head lelve, feet parallel, toes forward, arms at sides, palms facing
forward
Directional Terms
●​ Anterior / ventral: front
●​ Posterior / dorsal: back
●​ Superior / cranial: above
●​ Inferior / caudal: below (pelvis)
●​
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Medial: towards middle
Lateral: towards sides (thumb)
Proximal: closer to point of attachment
Distal: farther from point of attachment
●​ Prone: face down
●​ Supine: face up
●​ Superficial: closer to surface (the skin in superficial to the bones)
●​ Deep: farther from surface (the brain is deep to the skull)
Regional Terms
●​ Axial: main part of body (head, neck, trunk)
●​ Appendicular: upper and lower limbs attached to the axis
●​ Body planes: a plane or section is the 2D surface of a cut through 3D structure
○​ Sagittal plane: divides body/organ verrically into right/left sides
○​ Frontal plane: divide body/organ into anterior (front) and posterior (rear) portion
○​ Tranversrve plane: horizontally into upper and lower
Largest body compartments
●​ Dorsal (posteriror) cavity : brain and spinal cord
●​ Ventral (anterior) cavity
Serous Membranes (serosa) of the Anterior Body Cavity
●​ Double-layered thin membranes that cover wall and organ of thoracic (rib cage) and
abdominal-pelvic (largest cavity) cavities
○​ Parietal layer covers the cavity wall
○​ Visceral layer covers the organ
○​ Between layers is a lubricating fluid
secreted by cells of both layers
●​ The pleura: serous membrane that encloses
the pleural cavity (surround the lungs)
●​ The pericardium: encloses the pericardial
cavity (surrounds the heart)
●​ The peritoneum: encloses the peritoneal
cavity (surrounds several organs and
abdominopelvic cavity)