Chapter 06 (part 2) Neuronal Signaling and the Structure of the Nervous System Flashcards
Central nervous system
Brain
Spinal cord
Peripheral nervous system
Afferent division
Somatic sensory
Visceral sensory
Special sensory
Efferent division
Somatic motor
Autonomic motor
Sympathetic
Parasympathetic
Enteric
Forebrain parts
Cerebral hemispheres
Thalamus
Hypothalamus
Limbic system
main brain
Cerebellum
Brainstem
Forebrain
Forebrain
The cerebrum consists of
right and left cerebral hemispheres the diencephalon
Each cortex is divided into four lobes:
- Frontal
- Parietal
- Occipital
- Temporal
Forebrain
cerebral hemispheres consist of
cerebral cortex
corpus callosum
Forebrain
in the cerebral hemispheres
Outer gray matter composed primarily of cell bodies
Inner layer of white matter composed primarily of myelinated fiber tracts
the integrating area of the nervous system
cerebral cortex
Forebrain
in the cerebral hemispheres
a bundle of nerve fibers connecting the left and right cerebral hemispheres
corpus callosum
Two basic types of cells in the human cerebral cortex:
Pyramidal cells
Nonpyramidal cells
cortex is highly folded and results in ridges called _______ separated by grooves called sulci
gyri and sulci
cortex is highly folded and results in an area ____ larger than it would be if unfolded
4x
Two basic types of cells in the human cerebral cortex:
major output cells of the cortex, sending their axons to other parts of the cortex and CNS
Pyramidal cells
Two basic types of cells in the human cerebral cortex:
involved in receiving inputs into the cortex and in local processing of information
Nonpyramidal cells
Forebrain: Cerebral Cortex
- groups of gray matter that lie within the cerebral hemispheres
- Includes the basal nuclei (basal ganglia)
- important in controlling movement and posture and in more complex aspects of behavior
subcortical nuclei
Forebrain: Diencephalon parts
contains the thalamus, hypothalamus, and epithalamus
Forebrain: Diencephalon
a small mass of tissue that includes the pineal gland, which has a role in regulating biological rhythms
epithalamus
Forebrain: Diencephalon
- relay stations and important integrating centers for most inputs to the cortex
- plays a role in general arousal
- also is involved in focusing attention
thalamus
Forebrain: Diencephalon
- form the master command center for neural and endocrine
coordination
- Controls behaviors having to do with preservation of the individual (ex. eating and drinking) and preservation of the species (reproduction)
hypothalamus
Forebrain: Diencephalon
hypothalamus connected by a stalk to __________
important endocrine structure
pituitary gland
Gray and white matter in the forebrain areas
associated with learning, emotional experience and behavior, and a wide variety of visceral and endocrine functions
Limbic System
- important center for coordinating movements and for controlling posture and balance
- receives information from the muscles and joints, skin, eyes and ears, viscera, and the parts of the brain involved in control of movement
- implicated in some forms of learning
Cerebellum
nerve fibers that relay signals between the forebrain, cerebellum, and spinal cord pass through the brainstem
receives and integrates input from all regions of the central nervous system and processes a great deal of neural information
Brainstem
- absolutely essential for life
- neuron cell bodies running through the core of the brainstem
- involved in motor functions, cardiovascular and respiratory control
-regulate sleep and wakefulness and
focus of attention
reticular formation
contains nuclei involved in processing information for 10 of the 12 pairs of cranial nerves
Brainstem and The Cranial Nerves
Cranial Nerves
Carries input from receptors in olfactory (smell) neuroepithelium
Olfactory
Cranial Nerves
Carries input from receptors in eye
Optic
Cranial Nerves
Innervates skeletal muscles that move eyeball up, down, and medially, and raise upper eyelid; innervates smooth muscles that constrict pupil and alter lens shape for near and far vision
Transmits information from receptors in muscles
Oculomotor
Cranial Nerves
Innervates skeletal muscles that move eyeball downward and laterally
Transmits information from receptors in muscles
Trochlear
Cranial Nerves
Innervates skeletal muscles used for chewing
Transmits information from receptors in skin; skeletal muscles of face, nose, and mouth; and teeth sockets
Trigeminal
Cranial Nerves
Innervates skeletal muscles that move eyeball laterally
Transmits hearing and balance information from receptors in muscles
Abducens
Cranial Nerves
Transmits hearing and balance information from receptors in inner ear
Vestibulocochlear
Cranial Nerves
Innervates skeletal muscles of facial expression and swallowing; innervates nose, palate, and lacrimal and salivary glands
Transmits information from taste buds in front of tongue and mouth
Facial
Cranial Nerves
Innervates skeletal muscles involved in swallowing and parotid salivary gland Transmits information from taste buds at back of tongue and receptors in auditory-tube skin; also transmits information from carotid artery baroreceptors (blood pressure receptors) and from chemoreceptors that detect changes in blood gas levels
Glossopharyngeal
Cranial Nerves
Innervates skeletal muscles of pharynx and larynx and smooth muscle and glands of thorax and abdomen Transmits information from receptors in thorax and abdomen
Vagus
Cranial Nerves
Innervates sternocleidomastoid and trapezius muscles in the neck
Accessory
Cranial Nerves
Innervates skeletal muscles of tongue
Hypoglossal
fiber tracts run longitudinally through the cord
lies within the bony vertebral column
Spinal Cord
butterfly-shaped area composed of interneurons, the cell bodies and dendrites of efferent neurons, the entering axons of afferent neurons, and glial cells
gray matter
gray matter projecting toward the back of the body
dorsal horns
gray matter oriented toward the front
ventral horns
Areas surrounding the gray matter which consists of groups of myelinated axons
white matter
Spinal Cord
relay information from the brain to the spinal cord
Descending pathway
Spinal Cord
transmit information to the brain
Ascending pathway
Pathways also transmit information between different levels of the spinal cord
true
Axons that leave the spinal cord on the ventral side via the ventral roots
efferent neurons
- enter the spinal cord from the peripheral nerves enter on the dorsal side of the cord via the dorsal roots
- the dorsal root ganglia contain the cell bodies of these afferent neurons
afferent fibers
transmit signals between the CNS and receptors or effector organs
has 43 pairs of nerves
Peripheral Nervous System
Peripheral Nervous System
how many pairs of nerves
43
the 43 pairs of nerves consists of
12 pairs of cranial nerves
31 pairs of spinal nerves
cervical (8)
thoracic (12)
lumbar (5)
sacral (5)
coccygeal (1)
nerves that contain contain both afferent and efferent fibers
spinal nerves
nerves that contain only afferent fibers or only efferent fibers, or both
cranial nerves
Peripheral nervous system
control the muscles and glands and receive sensory input from the neck, shoulders, arms, and hands
cervical nerves
Peripheral nervous system
associated with the chest and upper abdomen
thoracic nerves
Peripheral nervous system
associated with the lower abdomen, hips, and legs
lumbar nerves
Peripheral nervous system
associated with the genitals and lower digestive tract
sacral nerves
Peripheral nervous system
associated with the tailbone
coccygeal nerves
Divisions of the PNS
1. Consists of a single neuron between central nervous system and skeletal muscle cells
2. Innervates skeletal muscle
3. Can lead only to muscle excitation
Somatic
Divisions of the PNS
1. Has two-neuron chain (connected by a synapse) between central nervous system and effector organ
2. Innervates smooth and cardiac muscle, glands, and GI
neurons
3. Can be either excitatory or inhibitory
Autonomic
Autonomic Nervous System
Enteric nervous system
Sympathetic NS
Parasympathetic NS
Autonomic Nervous System
often classified as a subdivision of the autonomic efferent nervous system
Specific for the gastrointestinal tract
Enteric nervous system
Sympathetic Nervous System
“fight or flight”
Sympathetic NS
Autonomic Nervous System
“rest and digest”
Parasympathetic NS
Autonomic Nervous System
the thoracolumbar division
has short pre-ganglionic and long post-ganglionic synapses
Sympathetic Nervous System
Sympathetic Nervous System major neurotransmitters
ACh at the pre-ganglionic synapse
usually NE and Epi at the post-ganglionic synapse
Autonomic Nervous System
recognized nonadrenergic and noncholinergic
Such as nitric oxide and other neurotransmitters
postganglionic neurons
Autonomic Nervous System
on smooth muscle, cardiac muscle, and gland cells are muscarinic receptors
on skeletal muscle fibers, innervated by the somatic motor neurons, are nicotinic receptors
acetylcholine receptors
Autonomic Nervous System
One set of postganglionic neurons in the sympathetic division form it
Upon activation, it release a mixture of about 80% epinephrine and 20% norepinephrine into the blood (plus other substances, such as dopamine, ATP, and neuropeptides)
More properly called hormones rather than neurotransmitters
Adrenal Medulla
Physical Support of the CNS
- Cranium
- Vertebrae
- Dura mater
- Arachnoid mater
- Pia mater
Cerebrospinal fluid
serves to support and to protect the structures of the CNS and PNS
Bone
are the membranes that line the structures and add additional support and protection
Meninges
Meninges
- Dura mater
- Arachnoid mater
- Pia mater
Meninges
* filled with CSF and contains large blood vessels
- In the superior sagittal sinus the arachnoid villi absorb the CSF into the venous blood system
Subarachnoid space
clear, colorless fluid that surrounds and protects the brain and spinal cord. It’s produced in the brain’s ventricles and flows throughout the central nervous system.
Cerebrospinal fluid
If the brain itself is inflamed it is called ___________ diagnosed by examining the CSF obtained via a lumbar puncture
encephalitis
Meninges three layers
- Cover and protect the CNS
- Protect blood vessels and enclose the venous sinuses
- Contain cerebrospinal fluid
- Form partitions in the skull
an inflammation of the meninges
Meningitis
Cerebrospinal Fluid (CSF) is secreted by ependymal cells of the
choroid plexus
the extracellular fluid of the CNS
- circulates through the subarachnoid space and ventricles
- reabsorbed by arachnoid villi
- maintains a stable and optimal environment
Cerebrospinal Fluid (CSF)
Substances in the brain’s capillaries are separated from the extracellular space
A continuous endothelium of the capillary walls and a thick basal lamina surrounding the capillaries
Blood-Brain Barrier
a protective mechanism that helps maintain a stable environment for the brain
Blood-Brain Barrier
The ______________ of the astrocytes surrounding the capillaries also contribute to the blood brain barrier
“feet”
How would the effects differ between a drug that blocks muscarinic acetylcholine receptors and one that blocks nicotinic acetylcholine receptors?
A drug that blocks muscarinic acetylcholine receptors would primarily affect smooth muscle function, causing effects like decreased salivation, slowed heart rate, and reduced gut motility, while a drug that blocks nicotinic acetylcholine receptors would primarily affect skeletal muscle contraction, leading to muscle weakness or paralysis, with minimal impact on the autonomic nervous system functions like heart rate or digestion
