This document provides an overview of the human sensory and motor systems. It describes the main sensory systems including taste, smell, hearing, balance, vision, cutaneous receptors, and proprioceptors. It explains how each system detects stimuli and transmits signals to the brain. It also outlines the motor system including bones, skeletal muscles, joints, and how muscles contract to enable movement. Sensory input allows the brain to perceive the environment, while motor output allows the body to respond through movement.
2. Senses
In order to be able to respond to stimuli, an
animal must be able to receive sensory input
Sense organs are specialized to receive one
type of stimulus
Sensory organs send nerve impulses to
the brain
The brain is what actually perceives the
information sent
3. Chemical Senses
Probably most primitive sense
Almost all animals can sense chemicals
in the environment
Ex. fly tastes with its feet
Ex. moths have receptors on antennae
4. Taste
Taste buds on the tongue
Receptor proteins for chemicals located
on microvilli on the cells of taste buds
When molecules bind, nerve impulses
generated
6. Taste
When you eat, the food causes many
nerve signals to be sent to the brain
The brain ‘averages’ all of the different
tastes to create the flavor of that food
7. Smell
Smell works in almost the same way as
taste, except the receptors are in the nose
Chemical receptors are located on cilia of
cells in the nose
Mixture of odors interpreted the same
way in the brain, as an average
8. Taste and Smell
Taste and smell are linked
Both trigger reflex responses to start
digestion
Revolting substances can trigger gag
reflex
Smells of smoke or predators can trigger
flight or fight response
9. Smell and Memory
Olfactory bulbs that process smell have
direct connections to the limbic system
in the brain
Remember this where memory and
emotions occur
10. Hearing and Balance
Human ear is used for both hearing and
balance
Hair cells are the receptors in the ear
They respond to mechanical stimulation
11.
12. Hearing
Outer ear collects sound waves
Tympanic membrane vibrates
Ossicles magnify sound about 20x
Stapes hits against the oval window
Vibrations from there passed to fluid in the
cochlea
Hair cells in cochlea move in the fluid,
stimulate nerves
13. Hearing
Each part of spiral organ (the cochlea, and
hair cells inside it) is sensitive to different
wave frequencies = pitch
Volume is an artifact of the amplitude of
the sound waves
Tone that is interpreted by the brain
depends on the distribution of the
stimulated hair cells
14. Balance
We can sense two types of movement: rotational
and gravitational
Rotational is sensed in the semicircular canals of
inner ear
3 canals- each corresponds to a different plane
of space
Movement of the head causes movement of the
fluid- stimulates hair cells, signal sent to
brain
15. Balance
Gravitational balance is sensed in the vestibule
of the inner ear
It has two parts, the utricle and the saccule,
which are membranous sacs
Contain hair cells, but set up is a bit
different- granules called otoliths rest on the
cilia of the hair cells, and their displacement
during head movement stimulates the cells
16. Vision
Receptors are sensitive to light
Human eye: one lens focuses light on
photoreceptors in the retina
Because we see from two vantage points
(two eyes) we have binocular vision,
which allows us to judge distance
17.
18. Vision
The cornea and the lens focus light on the
retina
Iris regulates how much light enters
through the pupil
Photoreceptors on the retina send nerve
impulses to the brain
Shape of lens controlled by ciliary muscles
19. Photoreceptors
Two types of photoreceptors: rods and
cones
Each uses a pigment that is broken by
light energy- this starts a chain reaction
that ends with the nerve impulse
20. Photoreceptors
Rods- ultra sensitive, throughout the retina
Night vision, peripheral vision, perception of
motion
Cones- located in the fovea- one part of retina
3 types of pigments for red, blue, green light
Respond to bright light
Color and detail vision
21. Cutaneous Receptors
Located in the skin
Respond to touch, pressure, pain, temperature
Temperature and pain receptors in
epidermis- outer layer of skin
Pressure and touch receptors in dermis-
inner layer of skin
See diagram on pg. 507
22. Proprioceptors
Located in joints and muscles
Tells the brain where the body is and how
it is moving
Essential for balance and equilibrium
as well as movement
23. Motor Systems
Skeleton- made of bone, is alive and able
to grow
Axial skeleton- skull, vertebral column,
sacrum
Appendicular skeleton- pectoral and
pelvic girdle
26. Skeletal Muscle
When skeletal muscle fibers contract, they
get shorter
Muscles contain two types of filaments-
actin and myosin
Myosin acts like an anchor, and in the
presence of ATP it will bind to actin and
pull on it, causing the actin fibers to get
closer to each other- this is contraction
27. Joints
3 types- immovable (ie cranium)
slightly movable (ie back)
freely movable (knee, hip, etc.)
Freely movable are synovial joints
Bound together by ligaments
Ligaments also create capsule around
joint that contains fluid for lubrication
28. Joints
Ball and socket joints- shoulder, hip
allow movement in all planes
Hinge joints- knee, elbow
Movement in one plane only
Muscles work in antagonistic pairs, ie biceps
and triceps, since they can only contract
Tendons connect muscles to bones
