BIOL 3060 Lecture Notes - Lecture 3: Efferent Nerve Fiber, Peripheral Nervous System, Axon Terminal

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champagnemink511

18 Oct 2018

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Interneurons make up almost all neurons in the body, they are found in the cns. In the pns there are efferent neurons that can drive the muscle contraction (they can have parts in the cns) and there are sensory neurons (afferent) In the neocortex, almost all neurons are nonmyelinated. Less current less channels to make propagation faster the voltage jumps from one node of. Very hard to recreate: divergent signaling: coming from axon, an axon can branch and give signals to different neurons. Synapses: chemical and electrical synapses, direct electrical connections are found in primitive organisms, they create rapid responses. There are some in the human brain, in areas where they are constantly firing ex, postural muscles. They couple many neurons and use electrical synapses. The two membranes are right on top of each other, direct contact, and between them there are channels called connexons/gap junctions (non-selective).

Related Questions

Nerve cells that conduct messages are called (1) ____. (2) _____ cells, which support and nurture the activities of neurons, make up less than half the volume of the nervous system. (3) _______ neurons respond to specific kinds of environmental stimuli, (4) ______ connect different neurons in the spinal cord and brain, and (5) ______ neurons are linked with muscles or glands. All neurons have a (6) _______ ________ that contains the nucleus and the metabolic means to carry out protein synthesis. (7) _______ are short, slender extensions of the (6), and together these two neuronal parts are the neuronsâ âinput zoneâ for receiving (8) _____. The (9) _____ is a single long, cylindrical extension away form the (10) ______; in motor neurons, the (11) ______ has finely branched (12) ________ that terminate on muscle or gland cells and are âoutput zones,â where messages are sent on to other cells. A neuron at rest establishes unequal electric charges across its plasma membrane, and a(n) (13) ____ ____ is maintained. Another name for (13) is the (14) _____ _____ _____; it represents an ability for the membrane to be disturbed. Weak disturbances of the neuronal membrane might set off only slight changes across a small patch, but strong disturbances can cause a(n) (15) _______ ______, which is an abrupt, short-lived reversal in the polarity of charge across the plasma membrane of the neuron. For a fraction of a second, the cytoplasmic side of a bit of membrane becomes positive with respect to the outside. The (16) ______ that travels along the neural membrane is nothing more than short-lived changes in the membrane potential. A. Neurons H. Sensory B. Motor I. Endings C. Interneurons J. Disturbance D. Cell body K. Signals (stimuli) E. Axon L. Voltage differential F. Dendrites M. Resting membrane potential G. Neuroglial N. Action potential

azureelk922

Which of the following statements is TRUE regarding sea anemones?

	None of the answer options is correct.
	Spongesânot sea anemonesâpossess what is considered to be the âsimplestâ nervous system found in animals.
	Because sea anemones are âsimpleâ organisms, these animals only possess motor neurons; sensory neurons or interneurons are never found in sea anemones.
	Although sea anemones possess ânet-likeâ nervous systems, these animals have brains located at their bases (near where they would attach to rocks).
	Although sea anemones lack definitive brains, they do possess ganglia that serve a similar function to the paired ganglia of flatworms.

Some people have low levels of calcium circulating in the blood, a condition known as hypocalcemia. While for many this disorder has little to no effect, for some it can be life-threatening. How could low levels of calcium harm an individual?

	Low levels of calcium would not have any effect on synaptic transmission.
	Low levels of calcium would cause sustained depolarization of the presynaptic cell.
	Low levels of calcium would result in fewer signals sent between the pre- and postsynaptic cell.

Cephalization is: the

	All of these choices are correct.
	development of a brain within the head of an animal.
	concentration of sensory organs within the head end of an animal.
	development of a âhead endâ in an organism.

Which of the following are TRUE about the resting membrane potential? (Select all that apply.)

	It results from voltage-gated sodium channels remaining open for long periods of time.
	It results from K⁺ ions diffusing out of the cell.
	It results from the sodium-potassium pump moving more Na⁺ ions out of the cell than K⁺ ions into the cell.

Afferent and efferent neurons differ in:

	their size.
	the directionality of the information they send.
	their pattern of myelination.

A neuron that responds to the environment is a(n):

	interneuron.
	homeostatic neuron.
	motor neuron.
	sensory neuron.

Which of the following is NOT the role of an interneuron?

	stimulating a muscle to contract
	conveying information from the internal environment of an animal
	relaying information from sensory to motor neurons
	maintaining homeostasis

Where are postsynaptic cell receptor proteins synthesized?

	the Golgi apparatus
	the lysosome
	the cytoplasm
	the rough endoplasmic reticulum

Inhibition of the flexor muscle during the knee-extension reflex is an example of:

	homeostasis.
	reciprocal inhibition.
	negative feedback.
	All of these choices are correct.

10.

What type of cells produce myelin for sensory neurons?

	pyramidal neurons
	glial cells
	melanocytes
	astrocytes

1. Kidneys help to maintain a proper balance of _________ within the body.

Phosphorous

Chloride

Potassium

Calcium Phosphate

ions

All of the above

2. The nervous system has how many major categories?

3. Which major category of the nervous system contains both the Somatic and the Autonomic divisions?

Central Nervous System

Peripheral Nervous System

Neither of these

Both of these

4. Which organ or structure helps to control the master endocrine gland (pituitary gland)?

The pancreas

The thorax

Peyerâs patches

The hypothalamus

6. This tiny gland is located at the base of the brain and produces the hormone melanin.

Parathyroid

Pituitary

Hypothalamus

Pineal

7. These glands are situated right above the kidneys. The hormones produced by these glands help us to cope with stress.

Thyroid

Parathyroid

Hypothalamus

Adrenals

8. The hormones necessary for the production of sperm are produced in the __________.

Kidneys

Testes

Ovaries

None of the above

9. The bloodstream assists the endocrine organs and structures by:

Removing hormones from the body

Delivering hormones to target cells

Delivering hormones to secretory cells

The bloodstream does not come into contact with endocrine structures or organs
10. The pancreas _____________.

Is a master gland that controls many other glands

Produces progesterone and oestrogen

Is a salivary gland

Regulates blood sugar, aid in digestion

11. The basic function of the endocrine system is ________ in nature.

Digestive

Reproductive

Hormonal

Proximal

13. Urinary tract infections (UTIs) are experienced by many people during their lifetimes. Urinary tract infections can involve any bacterial infection of the urinary system structures; the kidneys, bladder, ureters, or urethra. They are caused by bacteria entering the body through the urethra and traveling upward into the body. Symptoms can range from mild discomfort when urinating to extreme pain and the loss of blood during urination. They occur more frequently in women than men, and are often treated by antibiotics in addition to home remedies, such as drinking more water and drinking cranberry juice.

Based on what you have learned about the cause of urinary tract infections, which of the following precautions would help to prevent reoccurring infections?

Taking pain medication when symptoms occur

Placing a hot pack on the abdomen when symptoms occur

Practicing good hygiene Exercising regularly

14. The nervous system is divided into two major divisions: the Central Nervous System and the Peripheral Nervous System. Those divisions have structures that can be classified as belonging to two different subdivisions: the Somatic and the Autonomic systems. The nervous system can be summarized as a complex system of interconnected nerves and special cells called neurons that are used to transmit information (by means of small electrical impulses). Use the information in the table below to help answer questions about the nervous system. Division Organs & Structures Functions Central Nervous System (CNS) Brain Spinal Cord Nerves This is the bodyâs assessment and communication center. It analyzes the information received from the sensory neurons and responds. Peripheral Nervous System (PNS) Sensory Neurons Ganglia (clusters of neurons) Nerves that connect to one another and to the CNS The sensory neurons react to physical stimuli such as light, sound, heat, and pressure, and transmit that information to the CNS. Subdivisions Description Examples Somatic The Somatic system is comprised of nerves that connect the brain and spinal cord to the muscles of the body and sensory receptors in the skin. Reactions to physical stimuli like heat or light. Using your hand to touch Eating food Autonomic The Autonomic system largely involuntary. This system controls the unconscious functions of the body. Breathing Blood Pressure

Feeling overwhelmed or startled by exposure to very loud noises is likely a reaction to information collected by which subdivision of the nervous system:

Somatic

Autonomic

No answer text provided.

15. The thyroid gland is perhaps the most well-known member of the pancreatic system. Many adults are screened for thyroid problems during routine physical exams. This butterfly shaped gland is found at the base of the neck and releases hormones that affect the bodyâs metabolism (the way the body uses energy). The thyroidâs two main hormones are T3 and T4, and they affect many body functions, including: â¢ Breathing â¢ Heart rate â¢ Central and peripheral nervous systems â¢ Body weight â¢ Muscle strength â¢ Menstrual cycles â¢ Body temperature â¢ Cholesterol levels Two common disorders associated with the thyroid include hyperthyroidism and hypothyroidism. Some of the symptoms associated with these disorders are listed in the table below. Hyperthyroidism (Too many hormones released) Hypothyroidism (Too few hormones released) Anxiety Irritability or moodiness Nervousness, hyperactivity Sweating or sensitivity to high temperatures Hand trembling (shaking) Hair loss Missed or light menstrual periods Trouble sleeping Tiredness and fatigue Difficulty concentrating Dry skin and hair Depression Sensitivity to cold temperature Frequent, heavy periods Joint and muscle pain A patient complains of arthritis-like pain in the joints of her hands, but tests for arthritis come back negative. The doctor then suggests a thyroid function test. The doctor is most likely concerned about:

High levels of T3 and T4 hormones in the body

Low levels of T3 and T4 hormones in the body

No answer text provided.

No answer text provided

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BIOL 3060 Lecture Notes - Lecture 3: Efferent Nerve Fiber, Peripheral Nervous System, Axon Terminal

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