Nervous System (SENSES (Eye components and visual pathway (Vascular layer,…
Sensory Receptors based on stimulus origin
Inside, stimulus in internal organs, an example would be the feeling of fullness.
Stimulus orgin is muscle (including tendons) ligaments and joints.
outside, stimulus comes from environment, located in the skin and special senses.
Sensory receptor based on stimulus orgin
sensitive to light and, exteroreceptor
sensitive to chemicals, air and saliva, chemicals in blood, calcium, potassium, sodium.
Hot and cold
"Noxious" dangerous or painful.
: pressure, touch, vibration, stretch
Measures blood pressure (aorta, cartoid artery)
Eye components and visual pathway
Ciliary body: near and far sight depends on
Nourishes the other layers, deeply pigmented, absorbs light, prevents scattering.
Choroid=continuous with ciliary body (muscle that changes the shape of the lens)
Inner Layer-Retina or Neural layer
Photoreceptors, axons converge to form optic nerve.
sckera (white): dense connective tissue, anchor for muscles, preotective, gives shape to eye.
Cornea (clear): allows light into the eye, focusing light on retina.
PATH OF LIGHT
Light---cornea/focus---pupil---lens/focus---(posterior segment and vitrous humor---retina
Retina--optic nerve--optic chiasm (a)--optic track--mid brain--thalmus--primary visual cortex in occipital lobe.
many more rods than cones, sensitive to light, black and white, enables us to see in dimmed light.
Fewer cones than rods, allows us to see color, best in bright light..
Posterior to the iris, focusing light on the retina.
Color part of the eye, iris is anterior to the lens, intrinsic muscle-sphincter muscle, dilate and constrict.
Blind spot, no photoreceptors present.
Center of the mascula lutea,have clearest vision here.
Precise posterior pole, opposite of pupil
Posterior segment: largest cavity, filled with vitreous humor (gel like) maintains normal pressure, keeping it in place.
Posterior chamber: from iris to posterior chamber (filled with aqueous humor)
Anterior chamber: from iris to cornea (filled with aqueous humor)
Olfaction components and pathway
olfactory neurons, nerves, bulb, pseudostratified columnar epithelial with olfactory sensory neurons.
Olfactory receptors--olfactory sensory neurons with the olfactory bulb--olfactory tract (primary olfactory cortex in temporal lobe)--limbic system emotional brain
Roof of the nasal cavity
gustation components and pathway
Facial Nerve (VII):
transmits impulses from taste receptors in the anterior two-thirds of the tongue.
Glossopharyngeal Nerve (IX):
carries sensations from the tongues posterior third, as well as from the few buds in the pharynx.
Taste information reaches the brain stem and cerebral cortex through here. Occurs in three cranial nerves;
Vagus Nerve (X)
: carries taste impulses from the few taste buds on the epiglottis and lower pharynx.
Ear components and pathway
ear drum, thin and translucent. Boundary between external and middle ear. Shaped like a flattened cone, the apex of which points medially into the middle ear cavity.
: Transmits the vibrations of the eardrum across the cavity to the fluid in the internal ear.
Bony Labyrinth (maze):
a cavity in the petrous part of the temporal bone consisting of a system of twisting channels that has three parts.
continuous series of membrane walled sacs and ducts that fit loosely within the bony labyrinth and follow its contour.
The ear, shell shaped projection that surrounds the opening of the external acoustic meatus. Mostly elastic cartilage covered with skin.
External Acoustic Meatus:
a short tube running medially from the auricle to the ear drum.
ORGANIZATION OF NERVOUS SYSTEM
Consists of the brain and spinal cord, which occupy the cranium and the vertebral canal. Is the integrating and command center of the nervous system. Receives incoming sensory signals and dictates motor responses based on past experiences, reflexes and current conditions.
The part of the nervous system outside the CNS. Consists mainly of the nerves that extend from the brain and spinal cord. Cranial nerves carry signals to and from the brain. Spinal nerves carry signals to and from the spinal cord. These nerves serve as communication lines that link all regions of the body to the CNS.
Mainly traveling to parts of the body in skeletal muscle. Touch, pain, pressure, vibration and temperature.
Stimulates contraction of the skeletal muscle in the body.
senses whose receptors are spread widely throughout the outer tube of the body
Mainly to contents of ventral body cavity. Smooth muscle, glands, digestive system, respiratory system, urinary, arrector pili, muscles of skin, blood vessel walls, cardiac muscle, sweat glands.
regulates the contraction of smooth and cardiac muscle and secretion by the body's many glands.
Stretch, pain and temperature.
ANATOMY OF NERVOUS SYSTEM
Move blood through body
-bundle of axons
Made of Loose connective tissue
Fibrous connective tissue, surrounds each fascicle.
-insulation that covers some axons.
Collection of axons in in the PNS, most nerves have a combination of sensory and motor neurons.
-impulse generators and conductors that transmit nerve impulses away from their cell body. part of neuron that carries signal.
Tough, fibrous connective tissue, surrounds nerve.
- Single nerve cell
"eats" monitor, looks in nervous tissue for bacteria and parasites. Removes damaged nerve tissue and microbes.
simple cuboidal/columnar epithelium. lining spaces filled with cerebrospinal fluid
Most numerous, many processes that contact neurons and capillaries (small blood vessels. Supports neurons structurally. Maintains appropriate chemical environment (ie; calcium, sodium).
Wrap their plasma membranes around one portion of several axons.
Glial Cells- PNS
Regulates that exchange of materials in and out of neuron cell body. Structurally supportive.
Wrap plasma membrane around one portion of on axon. up to 100 times.
Major components of a neuron
- receivers, body can receive, contact and pass along messages. Like tree branches.
Thin processes of uniform diameter throughout theit length. Impulse generators and conductors that transmit nerve impulses away from cell body.
- clusters of free ribosomes and rough ER, renew plasma membrane, proteins within the cytosol.
Impulse generators and conductors that transmit nerve impulses away from cell body.
Nucleus and nucleolus
One or more branch from the axon,
(SOMA), consist of a single nucleus surrounded by cytoplasma.
- branches profusely at its end, spreads out like branches.
Terminal Boutons "axon terminals"-
Knob ends, very end.
Structural types of neurons
Have two processes that extend from opposite sides of the cell body. Very rare neurons that occur in some of the special sensory organs (inner ear, olfactory epithelium of the nose, retina of the eye.
short, single process that emerges from the cell body and divides like an inverted T into two long branches. Most neurons start out as bipolar whose processes fuse together near cell body during development.
Have more than two processes, numerous dendrites and a single axon, however some small multipolar neurons have no axon and rely on their dendrites to conduct signal.
Functional types of neurons
Unipolar, bipolar (special senses), cell bodies located in ganglia of PNS
Between neurons in CNS. 99.98% of all neurons in the body, complex neuro pathways.
Multipolar, cell bodies in the CNS----->motor neurons go to muscle and glands.