ANAPHY NEURO PART 3

Reflexes

Rapid, predictable, and involuntary responses to stimuli

Somatic reflexes

• Reflexes that stimulate the skeletal muscles

• - Involuntary, although skeletal muscle is normally under voluntary control

• • Example: pulling your hand away from a hot object

Autonomic reflexes

• Regulate the activity of smooth muscles, the heart, and glands

• • Example: regulation of smooth muscles, heart and blood pressure, glands, digestive system

Sensory receptor

reacts to a stimulus

Sensory neuron

carries message to the integration center

Integration center (CNS)

processes information and directs motor output

Motor neuron

carries message to an effector

Effector organ

is the muscle or gland to be stimulated

Two-neuron reflex arcs

• Simplest type

• - Sensory and motor neuron are usually found in the same place

• • Example: patellar (knee-jerk) reflex

Three-neuron reflex arc

• - Consists of five elements: receptor, sensory neuron, interneuron, motor neuron, and effector

• - The location of sensory neuron is different from that of motor neuron

• • Example: flexor (withdrawal) reflex

Cerebral Cortex ( Primary somatic sensory area )

• Located in parietal lobe posterior to central sulcus

• Receives impulses from the body's sensory receptors

• Pain, temperature, light touch (except for special senses)

Contralateral innervation

refers to a type of neural control in which a structure on one side of the body is controlled by the opposite side of the brain

Anterior Cerebral Cortex ( areas controlled )

• - Lower extremities

• - Genitals

• - Trunk

Posterior Cerebral Cortex ( areas controlled )

• Upper extremities

• - Face

• - Visceral organs

Broca's area (motor speech area)

• Involved in our ability to speak

• - Usually in left hemisphere (dominant hemisphere) at the base of the precentral gyrus; 90% (mga righthanded)

Wernicke’s area (sensory speech area)

Involved in comprehension of speech

Cerebral white matter

• Composed of fiber tracts deep to the gray matter

• - Tracts, such as the corpus callosum, are known as commissures

Basal Nuclei

"Islands" of gray matter buried deep within the white matter of the cerebrum

Diencephalon (interbrain)

• Sits on top of the brain stem

• Enclosed by the cerebral hemispheres

Thalamus

• Encloses the third ventricle

• - Relay station for sensory impulses passing upward to the cerebral cortex

Hypothalamus

• Important autonomic nervous system center. o Regulates body temperature, water balance, metabolism

• - Houses the limbic center for emotions - Regulates the nearby pituitary gland

• - Houses mammillary bodies o Reflex centers for olfaction (smell)

• Makes up the floor of the diencephalon

Epithalamus

• Forms the roof of the third ventricle.

• Houses the pineal body (an endocrine gland)

• produces melatonin