18) Consists of an ipsilateral withdrawal reflex and a contralateral extensor reflex; important in maintaining balance.…
The sensory receptor detects a stimulus. The interneurons receive inputs from sensory receptors and synapse on motor neurons. The effects on motor neurons can be excitatory or inhibitory. Lastly, motor neurons produce muscle contraction, and motor response. Reflexes often have effects in groups of motor neurons to different muscles; sometimes at different joints in the same limb or in a different limb. Reflexes are valuable tools for clinical evaluation of how our nervous system is functioning. For reflex to occur, all elements must be functional and our pathways must be intact. If reflexes are absent, the physician can diagnose where the pathway has been interrupted and can diagnose where function is compromised.…
B. The functions of components of a reflex arc are the receptor, sensory neuron, center, motor neuron and the effector. The receptor is responsible for activating a nerve impulse in a sensory neuron that responds to a change in the body’s internal and external environment. The sensory neuron conducts the impulse needed from the receptor to travel to its axonal end in the CNS.…
A muscle twitch is the fasciculation , or "muscle twitch", is a small, local, involuntary muscle contraction and relaxation visible under the skin.…
Define the terms reflex and spinal reflex and identify the components of a reflex arc.…
SPECIAL SENSES GENERAL PRESENTATION Overview of the Nervous System • Endocrine and nervous systems maintain internal coordination – Endocrine system: communicates by means of chemical messengers (hormones) secreted into to the blood – Nervous system: employs electrical and chemical means to send messages from cell to cell 12-2 Overview of the Nervous System • Nervous system carries out its task in three basic steps • Sense organs receive information about changes in the body and external environment, and transmit coded messages to the brain and spinal cord (CNS: central nervous system) • CNS processes this information, relates it to past experiences, and determines appropriate response • CNS issues commands to muscles and gland cells to carry out such a response 12-3 Overview of the Nervous System • Two major subdivisions of nervous system – Central nervous system (CNS) • Brain and spinal cord enclosed by cranium and vertebral column – Peripheral nervous system (PNS) • All the nervous system except the brain and spinal cord; composed of nerves and ganglia • Nerve—a bundle of nerve fibers (axons) wrapped in fibrous connective tissue • Ganglion—a knot-like swelling in a nerve where neuron cell bodies are concentrated 12-4 Overview of the Nervous System • Peripheral nervous system contains sensory and motor divisions each with somatic and visceral subdivisions – Sensory (afferent) division: carries signals from receptors to CNS • Somatic sensory division: carries signals from receptors in the skin, muscles, bones, and joints • Visceral sensory division: carries signals from the viscera (heart, lungs, stomach, and urinary bladder) 12-5 Overview of the Nervous System • Motor (efferent) division—carries signals from CNS to effectors (glands and muscles that carry out the body’s response) – Somatic motor division: carries signals to skeletal muscles • Output produces muscular contraction as well as somatic reflexes—involuntary muscle contractions –…
The reflex arc is the nerve pathway involved in a reflex action including at its simplest a sensory nerve and a motor nerve with a synapse between. The components are receptor, sensory neurons, motor neurons, relay neurons, and effector.…
Spinal reflexes don’t require input from brain – may be modulated by higher input from brain but integrated in spinal cord…
Babies at birth – most are born at 40 week and premature babies more often need a little more time to reach the same level of development as babies born in and after the 40th week. Most are born with just reflexes for survival at first. These would be swallowing, sucking reflexes to help feed. Rooting reflex baby will move its head if the cheek is touched to find a nipple or teat. Grasp reflex babies will grip objects touching their palm. Startle reflex they will often move arms outwards and clench fists is a sound movement or light suddenly startles them. Walking reflex when babies are held upright with their feet on a firm surface they usually mimic walking.…
C. The component of the reflex arc that is most likely to be damaged in Nick’s situation is the integrating center because one or more regions within the CNS relay impulses from sensory to motor neurons, so the impulses are never reaching the motor neurons and effectors.…
10/23/12: CHAPTER 9: MUSCLES AND MUSCLE TISSUE 10. 10/30/12: CHAPTER 10: THE MUSCULAR SYSTEM EXAM REVIEW: CHAPTERS 6-10 11. 11/6/12: EXAM II: CHAPTERS 6-10 12. 11/13/12: CHAPTER 11: FUNDAMENTALS OF NERVOUS SYSTEM AND NERVOUS TISSUE CHAPTER 12: THE CENTRAL NERVOUS SYSTEM 13. 11/20/12: CHAPTER 13: THE PERIPHERAL NERVOUS SYSTEM AND REFLEX ACTIVITY 14.…
|Startle reflex; when hearing a sudden sound or bright light will react by moving their arms outwards and clenching their fists. |…
Child laying on their front lies in a fetal position with knees tucked up. Child is unable to raise head or stretch limbs.…
The central nerves system receives sensory information from other parts of the body or the body's external environment and it transmits motor information to other parts of the body by way of the peripheral nervous system. Cranial nerve function is commonly assessed as part of a general physical examination of the head, eyes, ears, nose, throat, and neck. The tests provide a frame for how well our nervous system is taking in, processing, and also dispensing information to and from the Central Nerves System through the Peripheral Nervous…
3. Reflex actions arern’t voluntary. They’re automatic and defensive, usually without thought though you may be in a conscious state.…