AAKAASH VARMA, ROCCO CAPITINI, MICHAEL SCIORTINO, CHRISTINA GOTSIS
The following PowerPoint Presentation consists of a concise overview of Chapter 49 in
Campbell & Reece’s 7th Edition A.P. Biology Textbook, as well as a series of activities to
correspond with each of the following systems covered: sensory, skeletal, and muscular. This
PowerPoint Presentation is best viewed as a Slide Show. At the end there is a also a list of
online resources to accompany your academic endeavors into this field of biology. Good Luck!!!
TRANSDUCE STIMULUS ENERGY AND TRANSMIT SIGNALS TO THE CENTRAL NERVOUS SYSTEM
Sensations – action
potentials that reach brain
via sensory neurons
• PERCEPTIONS –
resulting
interpretations by brain
Sensory reception
involves stimulus
detection by sensory
receptors
• EXTERORECEPTORS –
detect external stimuli
• INTERORECEPTORS –
detect internal stimuli
MECHANORECEPTORS
• Sense physical deformation
• Bending of plasma membrane increases permeability to sodium and potassium
CHEMORECEPTORS
• Transmit information about total solute concentration of solution or individual molecules
• Involved in gustation (taste) and olfaction (smell)
ELECTROMAGNETIC
• Detect electromagnetic energy (e.g. visible light, electricity, and magnetism)
THERMORECEPTORS
• Respond to heat/cold
• Enable adaptation to regulate body temperature
NOCICEPTORS (A.K.A PAIN RECEPTORS)
• Naked dendrites in epidermis
• Enable detection of danger
TRANSDUCTION
AMPLIFICATION
TRANSMISSION
INTEGRATION
• Stimulus energy converted into change in membrane
potential (receptor potential)
• Result from opening/closing of ion channels in membrane of
receptor
• Stimulus energy strengthened by cells in sensory pathway
• May take place in sensory receptors or in accessory
structures
• Receptors release excitatory neurotransmitter, causing
sensory neuron to transmit action potentials to CNS
• Some may contain an axon, extending into CNS, others
release neurotransmitters at synapses.
• Begins when information is received
• May include a decrease in responsiveness during continued
simulation (sensory adaptation)
• Involves selectivity of receptors in information transmitted
to CNS
Light enters thru pupil, regulated by
size-changing iris
Reaches retina where it is captured by
specific photoreceptors, rods and cones,
which distinguish b/w shapes and colors,
respectively
Upon activation by light, rod cells
become polarized, and thus (de)activate
neuronal, bipolar cells that transmit light
signals through optic nerve to brain
Tympanic membrane vibrates at same
frequency as sound waves traveling
thru auditory canal
Causes small bones to transmit
vibrations to the oval window, which
creates pressure waves in cochlea fluid,
which transmit waves to round window
Hair cells of basilar membrane brush
against tectorial membrane, creating
changes in polarization
Lead to increased/decreased
neurotransmitter release to auditory
nerve
Chemoreceptors in taste buds of
tongue, bind to specific molecules
Once bound, ions diffuse through
channels in plasma membrane until
they reach sensory neurons, initiating
a signal transduction pathway
Ions are then transferred to sensory
neurons as neurotransmitters
Olfactory receptor cells use odorant receptors
of chemoreceptors to bind to odorant
molecules as they pass thru nasal cavity
These trigger signal transduction pathways
that, when reaching brain’s olfactory bulbs,
create action potentials that allow brain to
identify/distinguish odor
THE AURORA BOREALIS?
A PHOTORECEPTOR, A TYPE OF ELECTROMAGNETIC RECEPTOR!
MUSIC?
A MECHANORECEPTOR!
PERFUME?
AN ODORANT RECEPTOR, A TYPE OF CHEMORECEPTOR!
PAIN?
A NOCICEPTOR (A.K.A PAIN RECEPTOR)!
PIZZA?
A CHEMORECEPTOR!
HEAT?
A THERMORECEPTOR!
FUNCTION IN SUPPORT, PROTECTION, AND MOVEMENT
HYDROSTATIC
EXOSKELETON
ENDOSKELETON
• Fluid held under pressure in closed
body compartment
• Muscles to change shape of fluidfilled compartments to allow for
locomotion and form
• Cushions organs from shock
• Well suited for aquatic
environments but supports
crawling/burrowing on land
• Main type of skeleton in most
cnidarians, flatworms, nematodes,
and annelids
• Hard encasement deposited on
surface
• Molluscs: hinged calcareous
(calcium carbonate) shells
• Arthropods: cuticles composed of
chitin in a protein matrix and
hardened by calcium salts
• Molting occurs w/ each growth
spurt
• Hard supporting elements buried w/in
soft tissues
• Sponges: hard spicules of inorganic
material or softer protein fibers
• Echinoderms: hard plates (ossicles)
• Chordates: cartilage/bone
• Axial skeleton: skull, vertebral
column, and rib cage
• Appendicular skeleton: limb bones
and appendage-anchoring
pectoral/pelvic girdles
• Joints provide flexibility for body
movements
AN ENDOSKELETON (HUMAN)!
•Can survive in most different types of
environments if nourished well
•Has many supporting elements to provide
physical support on land
•Has a great range of flexibility
A HYDROSTATIC SKELETON (EARTHWORM)!
•Lives in moist soil
•Moves by a process known as peristalsis
•It is not raised off ground and is known to
crawl and burrow
AN EXOSKELETON (LOBSTERS)!
•Lives near abrasive shore
•Requires shielding from dangerous
materials, desiccation, and predators
•Must molt periodically
A HYDROSTATIC SKELETON (FLATWORMS)!
•Locomotion occurs by muscular alteration
of body cavities
•Subject to shock frequently
•Stays close to ground
AN ENDOSKELETON (MAMMALS)!
•Extremely flexible
•Has many soft tissues
•Requires a great deal of movement
AN EXOSKELETON (INSECTS)!
•Very fragile and require protection
•Present in many habitats
•Growth requires many moltings
OCCUR IN ANTAGONISTIC PAIRS AND MOVE SKELETAL PARTS BY CONTRACTING
MUSCLE FIBER-BUNDLES – each consist of a
single, multi-nuclear cell
MYOFIBRILS – thin actin and thick myosin
myofilaments that are bundled to form each
muscle fiber
SARCOMERES – contractile units of muscle
that repeat in unit-like frequencies in each
myofibril
I BAND, A BAND, and
H ZONE – contain
myofilaments
Z LINES – single actin
filaments that form
its boundaries
Thin (actin)
filaments slide
across thick
(myosin) filaments
Reduces width of I
bands and H zone
Shortens
sarcomere
Shortening of all
sarcomeres in a
myofibril shortens
entire myofibril
Graded contractions of whole muscles can be caused by:
Varying number of muscle
fibers that contract
Varying rate at which muscle
fibers are stimulated
Each branched muscle fiber is innervated
by 1 motor neuron that may synapse w/
multiple muscle fibers
1 action potential in a motor neuron
produces a twitch
MOTOR UNIT – 1 motor neuron and its
controlled muscle fibers
More rapidly delivered action potentials
produce a graded contraction by
summation
RECRUITMENT – activation of additional
motor neurons increases force (tension)
TETANUS – fusion of twitches into a
sustained contraction
Brownish-red pigment
that binds oxygen
CARDIAC MUSCLE
SMOOTH MUSCLE
• Found only in heart
• Striated cells that are electrically connected
by intercalated discs
• Can generate action potentials w/o input
from nervous system
• Found in walls of hollow organs
• Lack striations b/c their actin/myosin
filaments are not regularly arrayed along
cell length
• Contract slowly, but to a greater range than
striated muscles
• Contractions can be initiated by electrically
coupled muscles themselves or stimulated
by neurons of autonomic nervous system
MYOFIBRIL!
•Arranged longitudinally bundles of this
comprise a muscle fiber
•Made of myofilaments
CALCIUM (Ca2+) IONS!
•Bind to troponin complex to expose
myosin-binding sites on thin filament,
allowing for contraction
SARCOMERE!
•Repeating unit of a pattern of light/dark
bands, arranged by myofilaments
THIN FILAMENT!
•Filament w/ two strands of actin, and a
strand of regulatory protein
MOTOR UNIT!
•Collective term for a motor neuron and its
controlled muscle fibers
TETANUS!
•Sustained contraction brought about by
fusion of twitches that occur in quick
succession
SARCOPLASMIC RETICULUM!
•Its membrane pumps calcium (Ca2+) ions
from the cytosol into its interior to store
them and releases them when an action
potential is produced
TROPOMYOSIN!
•Regulatory protein that blocks myosinbinding sites, keeping fiber at rest
MUSCLE FIBER!
•1 cell w/ multiple nuclei, running muscle
length
TRANSVERSE (T) TUBULES!
•Infoldings of plasma membrane along
which action potentials move to spread
deep into a fiber
SENSORY SYSTEM:
•http://frank.mtsu.edu/~jshardo/bly2010/nervous/receptor.html
•http://www.spc.cc.tx.us/biology/mhartgraves/Bio2401/Lecture%20Notes/Sensory.pdf
•http://www.biology-online.org/9/8_sensory_systems.htm
•http://www.slideshare.net/NeurologyGuru/sensory-system
SKELETAL SYSTEM:
•http://www.mnsu.edu/emuseum/biology/humananatomy/skeletal/skeletalsystem.html
•http://www.innerbody.com/image/skelfov.html
•http://lyndarandy.tripod.com/skeletalsystem/id1.html
MUSCULAR SYSTEM:
•http://www.youtube.com/watch?v=EdHzKYDxrKc
•http://www.human-body-facts.com/muscular-system.html
•http://www.youtube.com/watch?v=gJ309LfHQ3M&feature=related
•http://www.besthealth.com/besthealth/bodyguide/reftext/html/musc_sys_fin.html
•http://www.ivy-rose.co.uk/HumanBody/Muscles/Muscle_Sliding-Filament.php