The Human Body Systems Guide
The human body is actually an amazing coalition of many different systems that work together to keep everything functioning correctly. For example, some systems handle food and energy, while others focus on taking in oxygen and moving it around the body. By learning about the different systems working inside the body, you can understand how everything works together to keep you healthy, growing, and strong.
Your brain and spinal cord are the major parts of the central nervous system. Different parts of your body send messages to the brain through the nerves and spinal cord. Once your brain gets these messages, it responds by interpreting the messages and reacting. The brain can then send instructions out to the body.
- Divisions of the Nervous System: The nervous system works to send signals throughout the body.
- The Nervous System: Doctors estimate that every person has about 100 billion neurons in their brain, which are responsible for sending and receiving messages.
- About the Nervous System: The central nervous system includes the brain and the spinal cord.
The endocrine system takes care of many different things. This system sends hormones out through the body, which are chemicals that tell cells what to do. Under the care of the endocrine system, lots of different activities occur. For instance, the body sleeps at night and wakes up in the morning, cells grow, and organs function in certain ways.
How The Brain Works
Considering everything it does, the human brain is incredibly compact, weighing just 3 pounds. Its many folds and grooves, though, provide it with the additional surface area necessary for storing all of the bodys important information.
The spinal cord, on the other hand, is a long bundle of nerve tissue about 18 inches long and ¾ inch thick. It extends from the lower part of the brain down through spine. Along the way, various nerves branch out to the entire body. These make up the peripheral nervous system.
Both the brain and the spinal cord are protected by bone: the brain by the bones of the skull, and the spinal cord by the set of ring-shaped bones called vertebrae that make up the spine. Theyre both cushioned by layers of membranes called meninges as well as a special fluid called cerebrospinal fluid. This fluid helps protect the nerve tissue, keep it healthy, and remove waste products.
The brain is made up of three main sections: the forebrain, the midbrain, and the hindbrain.
What Carries Messages From The Peripheral Nerves To The Brain
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The _______ nervous system includes the brain and spinal cord.
The _______ nervous system carries messages between the brain and the body.The _______ division of the peripheral nervous system is responsible for receiving inputs like temperature, texture, smell, and taste.The _______ nervous system controls things that you do not often think about, like digestion and breathing.The brain sends messages and commands back to the rest of the body through the _______ division of the peripheral nervous system.Taste molecules are unique because different molecules trigger _______ in the nose and mouth.Rods and _______ are the major types of cells responsible for receiving light and translating light into nerve signals.The optic nerves “cross over” from left to right and form an “X” at the _______.Explain what happens in the nervous system when you touch a hot pan in the kitchen. Your explanation should begin with the perception of temperature, and end with pulling away your hand.Question 2 options:
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Cerebrum The Cerebrum Is The Largest Part Of The Brain It Is Divided Into 2 Halves Called The Left And Right Cerebral Hemispheres The 2 Hemispheres Are Connected By A Bridge Of Nerve Fibres Called The Corpus Callosum The Right Half Of The Cerebrum Controls The Left Side Of The Body The Left Half Of The Cerebrum Controls The Right Side Of The Body The Cerebral Cortex Is The Outer Folded Part Of The Brain It Is Also Called The Grey Matter The Cerebral Cortex Is Mostly Made Up Of The Cell Bodies And Dendrites Of Nerve Cells Cell Bodies Contain The Nucleus And Other Main Parts Of The Cell Dendrites Are The Short Branching Fibres That Receive Signals From Other Nerve Cells The Inner Part Of The Cerebrum Is Called The White Matter It Is Mostly Made Up Of The Long Fibres Of A Nerve Cell That Send Signals To And From The Brain To The Rest Of The Body The Fatty Coating That Surrounds Axons Gives This Part Of The Brain A Whitish Appearance Each Hemisphere Is Divided Into 4 Sections Called Lobes These Include The Frontal Parietal Temporal And Occipital Lobes
Each lobe has different functions:
The frontal lobe controls movement, speech, behaviour, memory, emotions and intellectual functions, such as thought processes, reasoning, problem solving, decision-making and planning.
The parietal lobe controls sensations, such as touch, pressure, pain and temperature. It also controls the understanding of size, shape and direction .
The temporal lobe controls hearing, memory and emotions. The dominant temporal lobe also controls speech.
The occipital lobe controls vision.
What Does The Nervous System Do
Your nervous system uses specialized cells called neurons to send signals, or messages, all over your body. These electrical signals travel between your brain, skin, organs, glands and muscles.
The messages help you move your limbs and feel sensations, such as pain. Your eyes, ears, tongue, nose and the nerves all over your body take in information about your environment. Then nerves carry that data to and from your brain.
Different kinds of neurons send different signals. Motor neurons tell your muscles to move. Sensory neurons take information from your senses and send signals to your brain. Other types of neurons control the things your body does automatically, like breathing, shivering, having a regular heartbeat and digesting food.
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Sensory Modalities And Location
The general senses are distributed throughout the body, relying on nervous tissue incorporated into various organs. Somatic senses are incorporated mostly into the skin, muscles, or tendons, whereas the visceral senses come from nervous tissue incorporated into the majority of organs such as the heart or stomach. The somatic senses are those that usually make up the conscious perception of the how the body interacts with the environment. The visceral senses are most often below the limit of conscious perception because they are involved in homeostatic regulation through the autonomic nervous system.
Figure 14.5.6 â Dermatomes:
The various stimuli used to test sensory input assess the function of the major ascending tracts of the spinal cord. The dorsal column pathway conveys fine touch, vibration, and proprioceptive information, whereas the spinothalamic pathway primarily conveys pain and temperature. Testing these stimuli provides information about whether these two major ascending pathways are functioning properly. Within the spinal cord, the two systems are segregated. The dorsal column information ascends ipsilateral to the source of the stimulus and decussates in the medulla, whereas the spinothalamic pathway decussates at the level of entry and ascends contralaterally. The differing sensory stimuli are segregated in the spinal cord so that the various subtests for these stimuli can distinguish which ascending pathway may be damaged in certain situations.
The Brain And Spinal Cord Are The Central Nervous System Nerves And Sensory Organs Make Up The Peripheral Nervous System
Together, the central nervous system and the peripheral nervous systems transmit and process sensory information and coordinate bodily functions. The brain and spinal cord function as the control center. They receive data and feedback from the sensory organs and from nerves throughout the body, process the information, and send commands back out. Nerve pathways of the PNS carry the incoming and outgoing signals. Twelve pairs of cranial nerves connect the brain to eyes, ears, and other sensory organs and to head and neck muscles. Thirty-one pairs of spinal nerves branch out from the spinal cord to tissues of the thorax, abdomen, and limbs. Each nerve is responsible for relaying sensory information, sending motor commands, or both.
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What Are The Parts Of The Nervous System
The nervous system is made up of the central nervous system and the peripheral nervous system:
- The brain and the spinal cord are the central nervous system.
- The nerves that go through the whole body make up the peripheral nervous system.
The human brain is incredibly compact, weighing just 3 pounds. It has many folds and grooves, though. These give it the added surface area needed for storing the body’s important information.
The spinal cord is a long bundle of nerve tissue about 18 inches long and 1/2-inch thick. It extends from the lower part of the brain down through spine. Along the way, nerves branch out to the entire body.
Both the brain and the spinal cord are protected by bone: the brain by the bones of the skull, and the spinal cord by a set of ring-shaped bones called vertebrae. They’re both cushioned by layers of membranes called meninges and a special fluid called cerebrospinal fluid. This fluid helps protect the nerve tissue, keep it healthy, and remove waste products.
What Does The Spinal Cord Do
central nervous systemperipheral nervous systemDiagram
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Development Of The Nervous System
Before the formation of the nervous system in the embryo, 3e main cell layers become differentiated. The innermost layer, the endoderm, gives rise to the gastrointestinal tract, the lungs, and the liver. The mesoderm gives rise to the muscle, connective tissues, and the vascular system. The third and outer most layer, the ectoderm, formed of columnar epithelium, gives rise to the entire nervous system and skin.
During the third week of development, the ectoderm on the dorsal surface of the embryo between the primitive knot and the buccopharyngeal membrane becomes thickened to form the neural plate.
The plate, which is pear shaped and wider cranially, develops a longitudinal neural groove. The groove now deepens so that it is bounded on either side by neural folds. With further development, the neural folds fuse, converting the neural groove into a neural tube. Fusion starts at about the midpoint along the groove and extends cranially and caudally so that in the earliest stage, the cavity of the tube remains in communication with the amniotic cavity through the anterior and posterior neuropores.
Reflexes And Other Stimulus
The simplest type of neural circuit is a reflex arc, which begins with a sensory input and ends with a motor output, passing through a sequence of neurons in between. For example, consider the “withdrawal reflex” causing the hand to jerk back after a hot stove is touched. The circuit begins with sensory receptors in the skin that are activated by harmful levels of heat: a special type of molecular structure embedded in the membrane causes heat to change the electrical field across the membrane. If the change in electrical potential is large enough, it evokes an action potential, which is transmitted along the axon of the receptor cell, into the spinal cord. There the axon makes excitatory synaptic contacts with other cells, some of which project to the same region of the spinal cord, others projecting into the brain. One target is a set of spinal interneurons that project to motor neurons controlling the arm muscles. The interneurons excite the motor neurons, and if the excitation is strong enough, some of the motor neurons generate action potentials, which travel down their axons to the point where they make excitatory synaptic contacts with muscle cells. The excitatory signals induce contraction of the muscle cells, which causes the joint angles in the arm to change, pulling the arm away.
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Some Classifications Of The Cns Also Include
Central Nervous System Labeled Cerebrum Function And Structure Cerebrum Function Cerebrum Function Central Nervous System Pons Brain . The central nervous system consists of the brain and the spinal cord. Either of a pair of prominent oval structures in the medulla oblongata containing the olivary nuclei. It is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animalsthat is, all multicellular animals except radially symmetric animals such as sponges and jellyfish. These structures are involved in cerebellar motor learning and the perception of sound. It causes almost 10% of intellectual disability of otherwise unknown cause and can result in behavioral problems.
Future research will elucidate the role of defective glucose metabolism and the extent of the involvement of members of the glycolytic cascade nervous system labeled. Either of a pair of prominent oval structures in the medulla oblongata containing the olivary nuclei.
It is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animalsthat is, all multicellular animals except radially symmetric animals such as sponges and jellyfish. It can also play a role in developing major disorders like depression, heart disease and obesity 5. Understood with a thorough comprehension of.
What Conditions Can Affect Your Nervous System
Your nervous system has lots of protection. Your brain is guarded by your skull, and your spinal cord is shielded by small bones in your spine and thin coverings . Theyâre both cushioned by a clear fluid called cerebrospinal fluid.
Still, things can go wrong with your nervous system just like any other part of your body. When a disorder damages it, that affects the communication between your brain, your spinal cord, and your body. Examples of these disorders include:
- Infections like meningitis, encephalitis, or polio
- Physical problems like an injury, Bellâs palsy, or carpal tunnel syndrome
- Conditions like Parkinsonâs disease, multiple sclerosis, or Alzheimerâs disease
- Issues with your blood vessels, like strokes, transient ischemic attacks , or subdural hematoma
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What Conditions And Disorders Affect The Nervous System
Thousands of disorders and conditions can affect your nerves. An injured nerve has trouble sending a message. Sometimes its so damaged that it cant send or receive a message at all. Nerve injury can cause numbness, a pins-and-needles feeling or pain. It may be difficult or impossible for you to move the area thats injured.
Nerve damage can happen in several ways. Some of the most common causes of nerve damage include:
What Does Your Nervous System Do
The nervous system includes the brain, the spinal cord, and all the nerves in your body. It controls:
- Sight, hearing, taste, smell, and feeling .
- Movement, balance, and coordination. It also controls the actions of most other body systems, such as blood flow and blood pressure.
- Your ability to think and reason. It allows you to have thoughts, memories, and language.
The nervous system is divided into the brain and spinal cord and the nerve cells that control movements .
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Spinal Cord And Brain Stem
A sensory pathway that carries peripheral sensations to the brain is referred to as an ascending pathway, or ascending tract. The various sensory modalities each follow specific pathways through the CNS. Tactile and other somatosensory stimuli activate receptors in the skin, muscles, tendons, and joints throughout the entire body. However, the somatosensory pathways are divided into two separate systems on the basis of the location of the receptor neurons. Somatosensory stimuli from below the neck pass along the sensory pathways of the spinal cord, whereas somatosensory stimuli from the head and neck travel through the cranial nervesâspecifically, the trigeminal system.
The dorsal column system and the spinothalamic tract are two major pathways that bring sensory information to the brain . The sensory pathways in each of these systems are composed of three successive neurons.
Figure 14.5.1 â Ascending Sensory Pathways of the Spinal Cord:
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Everyday Connections The Myth Of Left Brain/right Brain
There is a persistent myth that people are right-brained or left-brained, which is an oversimplification of an important concept about the cerebral hemispheres. There is some lateralization of function, in which the left side of the brain is devoted to language function and the right side is devoted to spatial and nonverbal reasoning. Whereas these functions are predominantly associated with those sides of the brain, there is no monopoly by either side on these functions. Many pervasive functions, such as language, are distributed globally around the cerebrum.
Some of the support for this misconception has come from studies of split brains. A drastic way to deal with a rare and devastating neurological condition is to separate the two hemispheres of the brain. After sectioning the corpus callosum, a split-brained patient will have trouble producing verbal responses on the basis of sensory information processed on the right side of the cerebrum, leading to the idea that the left side is responsible for language function.
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