A&P Final Flashcards
Peripheral Nervous System
Provides links from outside world. All neural structures outside brain: sensory receptors, nerves, ganglia, efferent motor endings
Sensation
awareness of stimulus
perception
interpretation of meaning of stimulus
clarification of receptors
type of stimulus they detect
location in body
structural complexity
mechanoreceptors
respond to touch, pressure, vibration, stretch
thermoreceptors
sensitive to change in temp
photoreceptors
respond to light change
chemoreceptors
respond to chemical
nociceptors
respond to pain
exteroceptors
respond to stimuli arising outside body
touch, pain, pressure, temperature
interoceptors
inside body
chemical, tissue stretch, temperature
proprioceptors
respond to stretch
inform brain of ones movement
nonencapsulated (free) Nerve Endings
abundant in epithelia and connective tissue
most nonmyelinated (travel slow)
respond mostly to pain and temperature
Encapsulated Nerve Endings
all mechanoreceptors in connective tissue capsule
tacile corpuscle
discriminative touch
lamellar corpuscle
deep pressure and vibration
bulbous corpuscle
deep continuous pressure
muscle spindles
muscle stretch
tendon organ
stretch in tendon
joint kinesthetic receptors
joint position and motion
sensation
awareness of change in internal and external environment (someone walking behind you)
perception
conscious interpretation of stimuli (are you in danger?)
somatosensory
- receptor level- sensory receptors
- circuit level- process in ascending pathways
- perceptual level- process in cortical sensory areas
perceptual detection
ability to detect a stimulus has occurred
magnitude estimation
ability to detect how intense stimuli are
spatial discrimination
identify state or pattern of stimulation
spatial discrimination
identify state or pattern of stimulation
feature abstraction
mechanism has a preference for one stimulus than another
visceral pain
stimulation of visceral organ receptors
referred pain
pain in one body pain caused from another
spinal nerves
31 in all. 8 cervical (c1-c8) 12 thoratic (t1-t12) 5 lumbar (l1-l5) 5 sacral (s1-s5) 1 coccygeal (c0)
ventral root
contains motor (EFFERENT) fibers from ventral horn motor neurons
dorsal root
contains sensory (AFFERENT) fibers from sensory neurons in dorsal ganglia and conduct impulses from peripheral receptors
sacral plexus
l4-s4
serves as buttock, lower limb, pelvic structure
sciatic nerve resides here
sciatic nerve
longest and thickest nerve in body
composed of tibial and common fibular
dermatone
area of skin innervated by cutaneous branches of single spinal nerve (how spinal cord injury detected)
somatic reflexes
activate muscles (stove hot-pull hand away)
somatic reflexes
activate muscles (stove hot-pull hand away)
Central Nervous System (CNS)
CNS consists of brain and spinal cord
Cephalization
- Evolutionary development of rostral (anterior) portion of CNS
- Increased number of neurons in head
- Highest level reached in human brain
Ventricles of the Brain
- Filled with cerebrospinal fluid (CSF)
- Lined by ependymal cells
- Connected to one another and to central canal of spinal cord
- Lateral ventricles third ventricle via interventricular foramen
- Third ventricle fourth ventricle via cerebral aqueduct
Regions of the Adult Brain
- Cerebral hemispheres
- Diencephalon
- Brain stem (midbrain, pons, and medulla)
- Cerebellum
Anatomical Features of Cerebral Hemispheres
Surface markings
Ridges (gyri), shallow grooves (sulci), and deep grooves (fissures)
Longitudinal fissure
Separates two hemispheres
Transverse cerebral fissure
Separates cerebrum and cerebellum
Basic Regions of Cerebral Hemispheres
- Cerebral cortex of gray matter superficially
- White matter internally
- Basal nuclei deep within white matter
Cerebral Cortex
Site of conscious mind: awareness, sensory perception, voluntary motor initiation, communication, memory storage, understanding
Primary Motor Cortex
Long axons pyramidal tracts of spinal cord
Motor homunculi - upside-down caricatures represent contralateral motor innervation of body regions
Primary Motor Cortex
Long axons pyramidal tracts of spinal cord
Motor homunculi - upside-down caricatures represent contralateral motor innervation of body regions
Premotor Cortex
- Helps plan movements; staging area for skilled motor activities
- Controls learned, repetitious, or patterned motor skills
- Coordinates simultaneous or sequential actions
- Controls voluntary actions that depend on sensory feedback
Multimodal Association Areas: Anterior Association Area
Involved with intellect, cognition, recall, and personality
Multimodal Association Areas: Posterior Association Area
Plays role in recognizing patterns and faces, localizing us in space and understanding written and spoken language
Multimodal Association Areas: Limbic Association Area
Provides emotional impact that makes scene important and helps establish memories
Multimodal Association Areas: Limbic Association Area
Provides emotional impact that makes scene important and helps establish memories
Lateralization
Division of labor between hemispheres
Cerebral dominance
hemisphere dominant for language, math and logic
Thalamus
- Functions as the “Gateway” to the cerebral cortex
- Sorts, edits, and relays ascending input
- Mediates sensation, motor activities, cortical arousal, learning, and memory
Hypothalamic Function
- Controls autonomic nervous system
e. g., blood pressure, rate and force of heartbeat, digestive tract motility, pupil size - Physical responses to emotions
- Perception of pleasure, fear, and rage, and in biological rhythms and drives
- Regulates body temperature, hunger and satiety, water balance and thirst, sleep-wake cycle
- Controls endocrine system
Medulla Oblongata
- Autonomic reflex center
- Hypothalamus relays instructions via medulla
- Cardiovascular center
- Cardiac center adjusts force and rate of heart contraction
- Vasomotor center adjusts blood vessel diameter for blood pressure regulation
- Respiratory centers
- Generate respiratory rhythm
- Control rate and depth of breathing (with pontine centers)
Medulla Oblongata
- Autonomic reflex center
- Hypothalamus relays instructions via medulla
- Cardiovascular center
- Cardiac center adjusts force and rate of heart contraction
- Vasomotor center adjusts blood vessel diameter for blood pressure regulation
- Respiratory centers
- Generate respiratory rhythm
- Control rate and depth of breathing (with pontine centers)
Cerebellum
Role in thinking, language, and emotion
Cerebellum
Role in thinking, language, and emotion
Limbic System
Mediates emotional response and involved in memory processing
recognizes angry or fearful facial expressions, assesses danger, and elicits fear response
Puts emotional responses to odors
EEG
electroencephalogram
Epilepsy
Tonic-clonic (formerly grand mal) seizures
Most severe; last few minutes
Victim loses consciousness, bones broken during intense convulsions, loss of bowel and bladder control, and severe biting of tongue
Sleep Disorders
-Narcolepsy
>Abrupt lapse into sleep (REM) from awake state
>Often have cataplexy
>Fully awake but undergo sudden loss of >voluntary muscle control
-Orexins (“wake-up” chemicals from hypothalamus) thought to be destroyed by immune system
>Key to possible treatment
Short-term memory
temporary holding of information; limited to seven or eight pieces of information
Long-term memory
limitless capacity
Declarative memory
Explicit information: faces, names, words, dates
Nondeclarative Memory
Acquired through experience and repetition
Remembered by doing, hard to unlearn
Concussion
temporary alteration in function
Contusion
Contusion
Subdural or subarachnoid hemorrhage
may force brain stem through foramen magnum, resulting in death
Cerebral edema
swelling of brain associated with traumatic head injury
Parkinson’s disease
- Degeneration of dopamine-releasing neurons
- Basal nuclei deprived of dopamine become overactive tremors at rest
- Cause unknown
- Treatment with L-dopa; deep brain stimulation; gene therapy; research into stem cell transplants promising
Parkinson’s disease
- Degeneration of dopamine-releasing neurons
- Basal nuclei deprived of dopamine become overactive tremors at rest
- Cause unknown
- Treatment with L-dopa; deep brain stimulation; gene therapy; research into stem cell transplants promising
Epidural space
Cushion of fat and network of veins in space between vertebrae and spinal dura mater
