Chapter 13 Flashcards
blood vessels contract
, keeping the sweat glands closed (conserving heat),
the endocrine system
delivers chemical messages to your body and determines the rate of reactions. The endocrine system coordinates with the nervous system to ensure that processes are happening at a homeostatic speed.
Parathyroid Hormone (PTH)
A hormone secreted by the parathyroid that helps raise blood calcium concentrations.
Calcitriol
A hormone that is a form of vitamin D that aids in calcium absorption.
Calcitonin
A hormone secreted by the thyroid gland that helps lower blood calcium concentrations.
Aldosterone
A hormone that facilitates sodium reabsorption and potassium and hydrogen excretion.
Hypercalcemia
An excess of calcium in the blood. Heightened nervous and muscle excitability
Hypocalcemia
A deficiency of calcium in the blood. Nerves and muscle are less responsive to messages.
Perception
is the conscious awareness of stimuli received by sensory receptors.
Sensation
requires a stimulus, a sensory receptor, and conduction of an action potential to the CNS.
The somatic senses
include touch, pressure, temperature, proprioception, and pain.
The visceral senses
are primarily pain and pressure.
The special senses
are smell, taste, vision, hearing, and balance.
Primary receptors
have axons that transmit action potentials toward the CNS.
Secondary receptors
have no axons but release neurotransmitters.
Adaptation .
is decreased sensitivity to a continued stimulus.
Tonic receptors
adapt slowly;
phasic receptors
adapt rapidly
The spinothalamic tract - anterolateral
carries pain, temperature, light touch, pressure, tickle, and itch sensations.
The two major ascending systems
are the anterolateral and the dorsal-column/medial-lemniscal systems.
The ascending neurons of the spinoreticular tract - anterolateral
ascend both contralaterally and ipsilaterally, project to the reticular formation, and influence the level of consciousness.
The ascending neurons of the spinomesencephalic tract - anterolateral
carry action potentials from cutaneous pain receptors. The spinomesencephalic tract also contributes to eye reflexes.
The dorsal-column/medial-lemniscal system
carries the sensations of two-point discrimination, proprioception, pressure, and vibration.
The trigeminothalamic tract
carries sensory information from the face, nose, and mouth.
The spinocerebellar tracts
carry unconscious proprioception to the cerebellum from the same side of the body.
The direct motor pathways
maintain muscle tone and control fine, skilled movements in the face and distal limbs.
The indirect motor pathways
control conscious and unconscious muscle movements in the trunk and proximal limbs.
The speech area
is in the left cerebral cortex in most people.
The Wernicke area
comprehends and formulates speech.
The Broca area
receives input from the Wernicke area and sends impulses to the premotor and motor areas, which cause the muscle movements required for speech.
The right and left hemispheres
are connected by commissures. The largest commissure is the corpus callosum, which allows the sharing of information between hemispheres.
Short-term memory
requires long-term potentiation. The two types of memory are declarative and procedural.
Long-term memory
is converted from short-term by consolidation. The two types of memory are declarative and procedural.
The limbic system
is involved with emotions, motivation, mood, visceral functions, and memory. Olfactory stimulation is a major influence.
Free nerve endings
detect light touch, pain, itch, tickle, and temperature.
Merkel disks
respond to light touch and superficial pressure.
Hair follicle receptors
wrap around the hair follicle and are involved in the sensation of light touch when the hair is bent.
Pacinian corpuscles
, located in the subcutaneous tissue, detect pressure. In joints, they serve a proprioceptive function.
Meissner corpuscles
, located in the dermis, are responsible for two-point discriminative touch.
Golgi tendon organs
embedded in tendons, respond to changes in tension.
Ruffini end organs
are involved in continuous touch or pressure.
Muscle spindles
, located in skeletal muscle, are proprioceptors.
