Control and Coordination

1. Control and Coordination LS Chapter 18

2. The Nervous System • Group of organs that gathers, processes and responds to information gathered through the senses • Acts very quickly • Can be less than 1 second between gathering and responding • Touching something hot • The information gathered is called a stimulus • Can be a sight, sound, taste, smell or a feeling (touch) • The reaction to the stimulus is called a response • If the response is involuntary, it is a reflex • Vital in the maintenance of homeostasis • Keeps body’s internal conditions correct, no matter what is going on outside • Split into 2 parts-The Central Nervous System (CNS) and the Peripheral Nervous System (PNS)

4. Neurons • Neurons are the functioning unit of the nervous system • Work to relay sensory information to and from the brain • 3 main parts of a neuron • Dendrite-Receives information • Cell body-Processes information • Axon-Transmits information • 3 types of neuron • Sensory-Send information from senses to the brain or spinal cord • Motor-Sends information from the brain and spinal cord to tissues and organs • Interneurons-Connect sensory and motor neurons

5. Information Transmission • The area between neurons is called a synapse • Neurons relay information by releasing chemicals called neurotransmitters • These neurotransmitters travel across the synapse from an axon of one neuron to a dendrite of another

6. The Central Nervous System • The CNS includes the brain and spinal cord • Receives, processes, stores, and transfers information

7. The Brain • Control center of the body • Receives and sends information. Also processes and stores information. • 3 main divisions: • Cerebrum- Controls memory, language, and thought • Broca’s Area-Language center of the brain • Cerebellum- Controls voluntary muscle movement and balance • Muscle memory • Brain Stem- Controls involuntary actions • Heart, breathing, etc. • Connects brain to the spinal cord

8. Lobes of the Cerebrum • 4 lobes that have different functions • Frontal Lobe • Problem solving, emotion, reasoning, speaking, voluntary motor actions • Parietal Lobe • Sensation, reading, body orientation • Occipital Lobe • Vision, color perception • Temporal Lobe • Understanding language, behavior, memory, hearing

9. The Spinal Cord • Tube-like structure of neurons that extends from the brain stem • Transmits information to and from the brain • Protected by the vertebrae

10. The Peripheral Nervous System • Connects the CNS to the rest of the body • 2 parts • Somatic (SoNS)- Controls skeletal muscles and voluntary actions • Autonomic (ANS)- Controls smooth and cardiac muscles (involuntary) • Think: Autonomic=Automatic

11. Damage to the Nervous System • Physical injuries • Concussions- Traumatic injury to the brain • Can impair ability to think, concentrate, or remember • Can cause headaches and blurry vision • Can, in rare cases, change personality, and increase anxiety, anger, or loss of interest in usual activities • Huge problem in sports • Paralysis- inability to control parts of the body, or loss of sensation • Especially common in spinal cord injuries (broken neck/back) • Drugs kill neurons and impair abilities • Unlike most cells, neurons do not regrow or repair

14. Sensory System • Part of the Nervous System that detects or senses the environment • Humans have 5 senses • Sight • Hearing • Smell • Taste • Touch • The information is collected by specialized structures called receptors • Each sense uses different receptors

15. Vision • Eye collects and transmits to the brain • Parts of the eye • Cornea-outer membrane. Collects light and directs it into the eye. • Changes the direction to focus it • Iris and Pupil- Iris is the colored portion of the eye. Pupil is the black circle. • The iris controls the size of the pupil to adjust the amount of light entering. • Pupil decreases in size when bright, and dilates (increases in size) when dark to collect more light • Lens- Changes the direction of light again to focus it on the retina • Retina-area at the back of the eye that contains cells called photoreceptors • Photoreceptors, called rods and cones, send the information as electrical signals through the optical nerve to the brain

17. Vision Problems • Nearsightedness- Trouble focusing objects that are far away • The eye is longer, and focuses the image in front of the retina • Farsightedness- Trouble focusing on objects that are near • The eye is shorter than normal, and focuses the object behind the retina • Astigmatism- Irregular curvature of cornea or lens • Doesn’t bend light correctly, making image blurry • All can be corrected with corrective lenses

19. Hearing • Done by the ear • Sound waves are collected and transferred via auditory nerve to the brain • 3 parts of the ear • Outer Ear- Collects and directs soundwaves to the eardrum (tympanic membrane) • Middle Ear- Contains 3 tiny bones that are vibrated by the tympanic membrane • Called the malleus (hammer), incus (anvil), and stapes (stirrup) • These bones vibrate and transfer the sound to the inner ear • Inner Ear- Contains the cochlea, which is filled with fluid • The fluid moves and disrupts tiny hair cells, which connect to the auditory nerve

21. The Ear and Homeostasis • The ear is responsible for your sense of balance • As you move, fluid within the inner ear moves hair cells, which send information to your brain • Your brain interprets them and helps you maintain balance • This is also why you may get dizzy if you have an ear infection

22. Smell • Chemoreceptors in the nose collect sent particles from the air

23. Taste • Chemoreceptors in the mouth (a.k.a. taste buds) collect tastes and transfer them to the brain • Main tastes: Bitter, salty, sweet, sour, and umami • Umami is a savory taste • Especially MSG in processed foods • Not all taste buds sense all tastes • There are not certain regions of the tongue for each

24. Touch • Touch receptors in the skin feel temperature, pressure, and pain • Different receptors allow for feeling light touches (tickles) and harder touches (pokes or jabs) • There are more receptors in some areas than others • (where are you most ticklish?)

25. The Endocrine System • A group of organs and tissues that release chemicals (called hormones) into the blood • Slower than the nervous system • Endocrine glands release the hormones and they travel to other areas of the body • They bond to specific cells (lock and key)

26. Major Endocrine Glands • Hypothalamus and Pituitary Glands in the brain • Hypothalamus receives information from the body and signals the pituitary gland to release hormones • The Pituitary Gland releases hormones that regulate body functions and control the rest of the endocrine system • It also releases growth hormone which allows the body to grow • The Thyroid Gland regulates how the body uses energy (metabolism) • Located in the throat • The Thymus Gland, located in the chest, signals the body to fight infections

27. More Endocrine Glands • Adrenal Glands in the abdomen release adrenaline to help respond to stress • The Pancreas secretes insulin to control blood sugar • In females, ovaries release estrogen and produce egg cells • In males, testes release testosterone and produce sperm

29. The Endocrine System and Homeostasis • The glands of the endocrine system respond to stimuli and release hormones • Helps to regulate internal conditions • Feedback Loops • Negative Feedback-The glands release hormone only when needed • Continually happening in the body • Positive Feedback- The release of a hormone causes more to be released • Not as common • Childbirth, secretion of breastmilk