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
Describe the basal ganglia
Via the extrapyramidal motor system, the basal ganglia coordinate muscle movement as they receive information from the cortex and relay this information to the brain and the spinal cord
Smooth and steady posture
Parkinson’s disease, schizophrenia and obsessive compulsive disorder
Describe the components of the limbic system
Primarily associated with emotion and memory
The septal nuclei contain one of the primary pleasure centers
The amygdala is a structure that plays an important role in defensive and aggressive behaviors (docile and horny when damaged)
The hippocampus plays a vital role in learning and memory processes, specifically, the hippocampus helps consolidate information to form long-term memories and can redistribute remote emotions to the cerebral cortex, communicates with other portions of the limbic system through a long projection called the fornix
The anterior cingulate cortex is a connection with the frontal and parietal lobes, and is responsible for higher order cognitive processes, including motivation and impulse control
What are the two kinds of amnesia?
Anterograde which is characterized by not being able to establish new long-term memories. Where is memory for events that occurred before injury is usually intact
Retrograde refers to memory loss of events that transpired before injury
Describe the cerebral cortex
Can be divided into frontal, parietal, occipital, temporal lobe
Numerous bumps and forwards called gyri and sulci, divide the hemispheres
Describe the frontal lobe
The prefrontal cortex manages executive function and directing operations, it is an association area, it controls, impulse, perception, memory, emotion, and long-term planning
The primary motor cortex is a projection area and initiates a voluntary motor movement by sending neural impulses down the spinal cord toward the muscle
Brocas area for speech
Describe the parietal lobe
Somatosensory cortex is involved in somatosensory information processing, the projection area is the destination for all incoming sensory signals for touch pressure, temperature in pain
The central region of the parietal lobe is associated with spatial processing and manipulation
Describe the occipital lobe
At the very rear of the brain, it contains the visual cortex, which is sometimes called the striate cortex
Describe the temporal lobes
The auditory cortex is the primary site of most sound processing, including speech, Music, and other information
Warnicke’s area is associated with language reception and comprehension
The temporal lobe, also functions in memory processing, emotion, and language in this makes sense, considering the hippocampus is located deep inside the temporal lobe
Describe the two forms of cerebral hemisphere communication
Cerebral hemisphere communicates contra-laterally for example, the motor neurons
And other cases, like hearing the cerebral hemispheres communicate, with the same side of the body ipsilaterally
Describe the dominant, and non-dominant hemispheres
The dominant hemisphere is analytic, driving the Brocas area and the Warnicke’s area, it processes, letters, words, language related, sounds, speech, reading, writing, arithmetic, and complex voluntary movement
The non-dominant hemisphere is associated with intuition, creativity, music, cognition, and spatial processing, it is processes, faces, music, emotions, and geometry
A neurotransmitter does what
Used to communicate between neurons, something that mimics neurotransmitters is called an agonist, and something that blocks is called an antagonist
Acetyl choline
Neuro transmitter found in CNS and PNS, transmits nerve impulses to muscles in PNS, used by parasympathetic, nervous system, and small portion of the sympathetic nervous system, loss of cholinergic neurons on hippocampus is Alzheimer’s
Used by the efferent limb of the somatic nervous system
Mostly excitatory in CNS
Epinephrine and norepinephrine
Catecholamines monoamine
Alertness and wakefulness
Fighter flight
Norepinephrine more commonly acts at a local level, epinephrine, more often secreted from the adrenal medulla to act systematically as a hormone
Low levels of norepinephrine associated with depression and high levels are associated with anxiety and mania
Dopamine
Catecholamine
High concentrations in basal ganglia to help with smooth movements (Parkinson’s)
Schizophrenia
Serotonin
Biogenic amine neurotransmitter
Regulating mood, eating, sleeping, and dreaming
Plays a role in depression and mania
GABA
Produces inhibitory, postsynaptic, potentials, and just thought to play an important role in stabilizing neural activity in the brain. GABA exerts its effects by causing hyper polarization of the postsynaptic membrane.
Glycine does the same, but with chloride influx
Glutamate is excitatory
Peptides in neurotransmission
Neuromodulators, complicated chain of events and longer effects on the postsynaptic cell
endorphins
Natural pain killer
Peptide
Have actions simple to morphine or other opioids in the body
How do hormones travel?
Through the blood stream
Describe the relationship between the hypothalamus, endocrine system, nervous system, and the pituitary gland?
The hypothalamus and the pituitary gland are spatially close together and control is maintained through endocrine release of hormones into the hypophyseal portal system that directly connects them
Pituitary gland
Base of brain
Divided into anterior and posterior
Anterior pituitary
Released hormones that regulate activities or endocrine glands elsewhere
Controlled by hypothalamus
Where are the adrenal glands located?
On top of kidneys
How are the adrenal glands divided?
Adrenal medulla
Adrenal cortex
What does the adrenal medulla of the adrenal glands secrete?
Epi and Norepi as a part of the sympathetic NS
What does the adrenal cortex of the adrenal glands produce?
Corticosteroids- test and estrogen
Cortisol
Gonads
Tested in males ovaries in females
More sex hormone, E for woman T for man
Libido
High T causes aggression
