Chapter 3.1 Flashcards
Central nervous system CNS
The brain and the spinal cord
Peripheral nervous system PNS
Connects the brain and spinal cord to the rest of the body
Parts of the PNS
- Somatic nervous system
- Autonomic nervous system
Somatic nervous system
Consists of the axons conveying messages from the sense organs to the CNS and from the CNS to the muscles.
Autonomic nervous system
Controls the heart, intestines, and other organs.
Dorsal
Toward the back
Ventral
Toward the stomach
Anterior
Toward the front end
Posterior
Toward the rear end
Superior
Above another part
Inferior
Below another part
Lateral
Toward the side, away from the midline
Medial
Toward the midline, away from the side
Proximal
Located close to the point of origin or attachment
Distal
Located more distant from the point of origin or attachment
Ipsilateral
On the same side of the body (e.g., two parts on the left or two on the right)
Contralateral
On the opposite side of the body (one on the left and one on the right)
Coronal plane
A plane that shows brain structures as seen from the front
Sagittal plane
A plane that shows brain structures as seen from the side
Horizontal plane
A plane that shows brain structures as seen from above
Spinal cord
- Part of the CNS within the spinal column.
- The spinal cord communicates with all the sense organs and muscles except those of the head.
Dorsal root ganglia
The cell bodies of the sensory neurons are in clusters of neurons outside the spinal cord
Lamina
A row or layer of cell bodies separated from other cell bodies by a layer of axons and dendrites
Column
A set of cells perpendicular to the surface of the cortex, with similar properties
Tract
A set of axons within the CNS, also known as a projection. If axons extend from cell bodies in structure A to synapses onto B, we say that the fibers “project” from A onto B.
Nerve
A set of axons in the periphery, either from the CNS to a muscle or gland or from a sensory organ to the CNS
Nucleus
A cluster of neuron cell bodies within the CNS
Ganglion
A cluster of neuron cell bodies, usually outside the CNS (as in the sympathetic nervous system)
How does the spinal cord work?
Each segment of the spinal cord sends sensory information to the brain and receives motor commands from the brain. All that information passes through tracts of axons in the spinal cord
Two parts of the autonomic nervous system
- Sympathetic nervous system
- Parasympathetic nervous system
Sympathetic nervous system
- A network of nerves that prepare the organs for a burst of vigorous activity
- Consists of chains of ganglia just to the left and right of the spinal cord’s central regions (the thoracic and lumbar areas).
- These ganglia have connections back and forth with the spinal cord. Sympathetic axons prepare the organs for “fight or flight,” such as by increasing breathing and heart rate and decreasing digestive activity.
Parasympathetic nervous system
- Generally the opposite of, sympathetic activities.
- For example, the sympa- thetic nervous system increases heart rate, and the parasym- pathetic nervous system decreases it
The 3 major divisions of the brain
- The hindbrain
- The midbrain
- Forebrain
Hindbrain
The posterior part of the brain, consists of the the medulla, the pons, and the cerebellum.
Brainstem
The medulla and pons, the midbrain, and certain central structures of the forebrain
Medulla
An enlarged extension of the spinal cord
Cranial Nerves
Originating in the medulla control vital reflexes such as breathing, heart rate, vomiting, salivation, coughing, and sneezing.
Because opiate receptors, which suppress activity, are abundant in the medulla, opiates can produce a dangerous decrease in breathing and heart rate.
Pons
lies anterior and ventral to the medulla. Like the medulla, it contains nuclei for several cranial nerves.
Cerebellum
a large hindbrain structure with many deep folds. It has long been known for its contributions to the control of movement
Major structures of the forebrain
Thalamus, hypothalamus
Cerebral cortex, hippocampus, basal ganglia
Major structures of the Midbrain
Tectum, tegmentum, superior colliculus, inferior colliculus, substantia nigra
Major structures of the Hindbrain
Medulla, pons, cerebellum
The midbrain
in the middle of the brain
Tectum
The roof of the midbrain
Superior colliculus and inferior colliculus
- The swellings on each side of the tec-tum
- Both are important for sensory processing
- The inferior colliculus for hearing
- the superior colliculus for vision.
Tegmentum
- Under the tectum
- The intermediate level of the midbrain
substantia nigra
Gives rise to a dopamine-containing pathway that facilitates readiness for movement.
The cranial Nerves
- Olfactory
- Optic
- Oculomotor
- Trochlear
- Trigeminal
- Abducens
- Facial
- Statoacoustic
- Glossopharyngeal
- Vagus
- Accessory
- Hypoglossal
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Major function of the olfactory nerve
Smell
Major function of the opric nerve
Vision
Oculomotor
Control of eye movements; pupil constriction
Major function of the trigmenial
Skin sensation from most of the face; control of jaw muscles for chewing and swallowing
Major function of the facial nerve
Taste from the anterior two thirds of the tongue; control of facial expressions, crying, salivation, and dilation of the head’s blood vessels
Major function of the statoacoustic nerve
Hearing
Major function of the glossopharyngeal
Taste and other sensations from throat and posterior third of the tongue; control of swallowing, salivation, throat movements during speech
Major function of the vagus nerve
Sensations from neck and thorax; control of throat, esophagus, and larynx; parasympathetic nerves to stomach, intestines, and other organs
Major function of the hypoglossal nerve
Control of muscles of the tongue
Forebrain
- consists of two cerebral hemispheres, one on the left and one on the right.
- Each hemisphere is organized to receive sensory information, mostly from the contralateral (opposite) side of the body.
- It controls muscles, mostly on the contralateral side, by way of axons to the spinal cord and the cranial nerve nuclei.
Limbic system
- the olfactory bulb, hypothalamus, hippocampus, amygdala, and cingulate gyrus
- Forms a border around the brainstem
Hypothalamus is essential for xx
- Control of eating, drinking,
- temperature control,
- reproductive behaviors
Amygdala is essential for xx
- for evaluating emotional information, especially fear
Thalamus
- A pair of structures (left and right) in the center of the forebrain.
- Most sensory information goes first to the thalamus, which processes it and sends output to the cerebral cortex.
Hypothalamus
- a small area near the base of the brain just ventral to the thalamus
- Partly through nerves and partly by releasing hormones, the hypothalamus conveys messages to the pituitary gland, altering its release of hormones.
Pituitary gland
- An endocrine (hormone-producing) gland attached to the base of the hypothalamus
- In response to messages from the hypothalamus, the pituitary synthesizes hormones that the blood carries to organs throughout the body.
Basal Ganglia
- A group of subcortical structures lateral to the thalamus, include three major structures:
- the caudate nucleus,
- the putamen,
- globus pallidus
Damage impairs movement
Nucleus basalis
- receives input from the hypothalamus and basal ganglia and sends axons that release acetylcholine to widespread areas in the cerebral cortex
- For arousal, wakefulness, and attention
Hippocampus
- a large structure between the thalamus and the cerebral cortex, mostly toward the posterior of the forebrain
- critical for certain types of memories, especially memories for individual events
Ventricles
Your brain floats in a bath of cerebrospinal fluid. This fluid also fills large open structures, called ventricles, which lie deep inside your brain. The fluid-filled ventricles help keep the brain buoyant and cushioned.
Cerebrospinal fleud CSF
a clear fluid similar to blood plasma. CSF fills the ventricles, flow- ing from the lateral ventricles to the third and fourth ven- tricles.
Meninges
membranes that surround the brain and spinal cord.