PHED-4547EL Lecture Notes - Lecture 25: Cranial Cavity, Efferent Nerve Fiber, Venous Blood
27 Apr 2020
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Neurons (nerve cells) and neuroglia (supporting cells) Sensory or afferent nerve: transmits impulses to the nervous system. Motor or efferent nerve: transmits impulses from brain or spinal cord to muscle. Transmission of a nerve impulse via neurotransmitters: acetylcholine, norepinephrine, dopamine. Arachnoid: middle: subarachnoid space: space between arachnoid and pia that contains, cerebrospinal fluid (csf, strands of arachnoid connective tissue. Pia: thin inner membrane: adheres to brain and spinal cord. Midbrain and hindbrain form remainder of adult brain. Mesoderm surrounding neural tube forms cranial cavity, vertebral bodies, and surrounding structures. Controlled by nerve impulses originating in motor neurons of the cerebral cortex (cortical neurons) Extrapyramidal system regulates muscle groups concerned with automatic functions such as walking. Flaccid paralysis: destruction of motor neurons by disease. Interruption of reflex arc responsible for muscle tone: muscle deprived of innervation, low muscle tone (tension in resting muscles, peripheral nerve destruction. Spastic paralysis: reflex arc not disturbed.
