Curriculum Outcomes to be covered in this Unit

Transcription

1 The Nervous System

2 Curriculum Outcomes to be covered in this Unit Compare and contrast mechanisms used by organisms to maintain homeostasis (317) Explain how different plant and animal systems, including vascular and nervous systems, help maintain homeostasis (317-1) Analyze homeostatic phenomena to identify the feedback mechanisms involved (317-2) Evaluate the impact of viral, bacterial, genetic and environmental disease on an organism s homeostasis (317-4) Evaluate, considering ethical issues, the consequences of medical treatments such as radiation therapy, cosmetic surgery, and chemotherapy (317-5) Describe how the use of prescription and nonprescription drugs can disrupt or help maintain homeostasis (317-7)

3 The nervous system is the body s information gatherer, storage center and control center. The nerves do not form one single system, but several which are interrelated.

4 The nervous system has 4 functions that enable the body to respond quickly. 1. Gather information both from the outside world and from inside the body. 2. Transmits the information to the processing area of the brain and spinal cord. 3. Processes information to determine best response.

5 4. Sends information to muscles, glands, and organs so they can respond correctly.

6 Two Main Divisions of the Nervous System 1. Central Nervous System (CNS) 2. Peripheral Nervous System (PNS)

7 Vertebrate Nervous System Nervous System Peripheral Nervous Central Nervous System Somatic Nerves Brain Spinal Cord Autonomic Nerves Sensory Motor Voluntary Sympathetic Parasympathetic Involuntary

8 Central Nervous System Contains nerves of the brain and spinal cord. Acts as a coordinating centre for incoming and outgoing information. (Other functions include vision, speech, hearing, memory, consciousness, learning, etc.)

9 Within the central nervous system (CNS) two main parts are identified: 1. Brain 2. Spinal Cord

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11 Brain The brain is inside the skull and weighs about 1.5 kg.

12 Protection of the brain: 1. Cranium the bones of the skull protect the brain from injury 2. Meninges The brain tissue is covered by a set of three membranes referred to as meninges. Three layers are: dura mater (this is outermost layer), arachnoid mater (middle layer), and pia mater (innermost layer).

13 3. Cerebrospinal fluid found between the layers of meninges. It is also found in spinal cord. Helps to cushion the brain against shock. 4. Blood-Brain Barrier a filtration system which controls the types of materials entering the brain s cells. It will allow the needed materials, like glucose and oxygen, to enter the cells, but prevents harmful materials from entering.

14 Parts of the Brain The brain consists of three major parts: 1. Forebrain, 2. Mid-Brain, 3. Hind-Brain

15 Forebrain includes the cerebrum, thalamus and hypothalamus Cerebrum humans have the largest cerebrum making us capable of language, reasoning and personality. The cerebrum is divided into specific lobes: A. frontal lobe behind the forehead - controls movement of voluntary muscles - the center of intellectual activities (memory, speech) and personality - Smell

16 B. Parietal Lobe found at the top and sides of the head - Interprets many skin sensations (touch taste) - Controls some emotions - Controls some speech C. Occipital lobe - At base of head - Controls vision

17 Temporal Lobe around temples - controls hearing, memory, and language

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19 Thalamus located below the cerebrum - sorts and interprets sensory information - sends information to the conscious part of the brain Hypothalamus located below thalamus - an endocrine gland which produces hormones - controls hunger, aggression, pleasure, blood pressure, sleep

20 Midbrain is relay center Hindbrain found posterior to the midbrain and joins with the spinal cord. Three parts: 1. cerebellum 2. pons 3. medulla oblongata

21 Cerebellum located immediately beneath the cerebrum - largest section of hindbrain - controls limb movement - balance and muscle tone

22 Pons relay station that passes information between the two regions of the cerebellum and the medulla oblongata.

23 Medulla Oblongata posterior region of the hindbrain, located at the base of skull. - Regulates involuntary muscle action such as breathing, the diameter of the blood vessels and heart rate. - Nerve tracts from the spinal cord and higher brain centers run through it. - Acts as the connection between the peripheral and central nervous systems. - Acts as the coordinating centre for the autonomic nervous system.

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26 Spinal Cord The spinal cord extends from the medulla oblongata through the bony arch of each vertebrae, along the length of the spine. Carries sensory nerve message from receptors to the brain and relays motor nerve messages from the brain to the muscles. 31 pairs of spinal nerves branch off the cord; 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal.

27 If the spinal cord were severed, all parts of the body controlled by the nerves below the point of the severance would be paralyzed. There are two types of nerve tissue that make up the spinal cord : 1. Grey matter 2. White matter

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31 Assigned Readings: P. 412 and half of 413 P. 427, 428, 429 and 430 P. 434 Summary