Nervous System Physio Flashcards
Describe the function of an interneuron.
Upon connection with the sensory neurons, they relay pain impulses up to the brain, but also send signals to the muscles affected directly rather than waiting on a response from the brain.
What are the three types of nerve cells in the nervous system?
Sensory neuron: also known as afferent neurons, transmit sensory information from receptors to the spinal cord and brain
interneuron: found between other neurons and are the most numerous, vital in reflex arc
motor neuron: efferent neurons, transmit motor information from the brain and spinal cord to muscles and glands
What is the nervous system divided into?
Central: composed of the brain and spinal cord
Peripheral: made up of nerve tissues, and fibers outside the brain and spinal cord, 31 pairs of nerves, emanating from the spinal cord, which are called spinal nerves, and 12 pairs of nerves, emanating directly from the brain called cranial, nerves, or factoring optic nerves, which are the first and second cranial nerves are structurally outgrowths of the central nervous system, but are still considered components of the peripheral nervous system
What can the peripheral nervous system be divided into?
Somatic: consist of sensory and motor neurons, transmit information toward the CNS through afferent fibers, motor impulses, travel from the CNS back to the body along efferent fibers
Autonomic: generally, regulates, heartbeat, respiration, digestion, glandular secretions, and temperature control
Manages involuntary muscles associated with internal organs and glands
Describe the two branches of the autonomic nervous system.
Parasympathetic: conserve energy
Resting, sleeping, reduce heart rate, constricted bronchi
Manages digestion by increasing peristalsis and exocrine secretions
Acetylcholine is the neurotransmitter responsible for parasympathetic responses in the body
Sympathetic: activated by stress
Increase heart rate
Redistributes blood to muscles of locomotion
Increases blood glucose concentration
Relaxes bronchi
Decreases digestion and peristalsis
Dilating the eyes to maximize light intake
Releases epinephrine into the bloodstream
List and describe the nerves of the parasympathetic nervous system.
nerve III, nerve VII: constrict pupils
nerve VII, nerve IX: stimulates flow of saliva
nerve x: constricts bronchi, slows heartbeat, inhibits release of glucose, stimulates bile release, inhibits adrenaline production, stimulates peristalsis and secretion
Pelvic splanchnic nerves: contracts bladder, promotes erection
Describe the functions of the sympathetic nervous system.
Dilate pupils
Inhibit salivation
Relaxes bronchi
Accelerates heartbeat
Stimulates glucose production and release
Inhibits peristalsis and secretion
Secretion of adrenaline or noradrenaline
Inhibits bladder contraction
Stimulates orgasm
Stimulus sweating or piloerection
Release epinephrine into the bloodstream
What are the major divisions of the brain?
Forebrain:
Cerebral cortex- complex perceptual, cognitive, and behavioral processes
Language processing, problem-solving, impulse control, long-term planning
Basal ganglia- movement
Limbic system- emotion and memory
Thalamus- sensory relay station
Hypothalamus- hunger and thirst, emotion
Midbrain:
Inferior and superior colliculi- sensory motor reflexes
Hindbrain:
Cerebellum- refined motor movements
Medulla oblongata- heart, vital reflexes
Reticular formation- arousal and alertness
Pons- communication within the brain, breathing
Describe the relationship between the structures of the hindbrain.
Overall that controls balance, motor coordination, breathing, digestion and general arousal
During embryonic development, the rhombencephalon (hindbrain) divides to form the myelencephalon (medulla oblongata) and the metencephalon (pons and cerebellum)
The pons contains sensory and motor pathways between the cortex and medulla
The cerebellum helps maintain posture and balance and coordinates body movements
Describe the relationship between the structures of the midbrain.
The mid brain is also known as the mesencephalon, it receives sensory and motor information from the rest of the body, involuntary reflex responses triggered by visual or auditory stimuli, the superior colliculus receives visual sensory input in the inferior colliculus receives sensory information from the auditory system
Describe the relationship between the structures of the forebrain
The forebrain is also known as the prosencephalon and is responsible for complex perceptual, cognitive, and behavioral processes, it is associated with emotion and memory, it has the greatest influence on human behavior
During prenatal development, the prosencephalon divides to form the telencephalon (cerebral cortex, basal, ganglia, limbic system) and the diencephalon (thalamus, hypothalamus, posterior pituitary gland, and pineal gland)
Describe some of the methods of studying the relationship of brain regions and behavior.
- Study brain lesions in lab animals: extirpation, inserting, tiny electrodes and applying intense heat, cold, or electricity, stereotactic instruments to produce higher resolution images of the brain
- Cortical maps: electrically, stimulating the brain, local anesthesia, awake patient
- EEG: placing several electrodes on scalp, broad pattern of electrical activity, can dust be detected and recorded because this procedure is non-invasive, EEG are commonly used on human subjects, electrical activity generated by larger groups of neurons can be studied
- rCBF: detect broad patterns of neural activity, based on increased blood flow to different parts of the brain, patient inhales, radioactive gas and device detects radioactivity levels in the bloodstream
- CAT: x-ray and computer processing
- PET: radioactive sugars injected and absorbed into the body and its dispersion and uptake throughout the target tissue is imaged
- MRI: magnetic field that interacts with hydrogen atoms is used to map out hydrogen dense region of the body
- fMRI: measures changes associated with blood flow, same base technique as MRI
Describe the thalamus.
Relay station for incoming sensory information, including all senses, except for smell, thalamus sorts and transmits them to the appropriate areas of the cerebral cortex
Describe the hypothalamus.
Feeding, fighting, flighting, and fucking
Control endocrine functions, and autonomic nervous system
Homeostatic functions, divided into lateral hypothalamus and ventromedial hypothalamus and anterior hypothalamus
Describe the lateral hypothalamus
Special receptors, thought to detect when the body needs more fluid or food
Describe the ventromedial hypothalamus
Provide signals to stop eating
Describe the anterior hypothalamus.
Control sexual behavior, regulates sleep and body temperature
What are the two glands of the diencephalon?
Posterior pituitary, which is comprised of axonal projections from the hypothalamus and is the site of release for hypothalamic hormones, vasopressin, and oxytocin
The pineal gland secretes, melatonin, and is a key player and several biological rhythms
