Nervous System Lesson 2 PDF

05/09/2024 Physiological Basis of Behavior 1 Mechanisms of Behavior ✘ Receiving Mechanism – sense organs ✘ Connecting Mechanism – nervous system ✘ Reacting Mechanism – muscles and e...

05/09/2024 Physiological Basis of Behavior 1 Mechanisms of Behavior ✘ Receiving Mechanism – sense organs ✘ Connecting Mechanism – nervous system ✘ Reacting Mechanism – muscles and endocrine system 2 2 1  05/09/2024 Sense Organs Stimulus (Information Receptors (Actual part within the sense Part of the Brain that will Sense Organs received by the senses) organs that will receive the stimulus) process information Vision Light Retina (Rods/Cones) Occipital lobe Cochlea Temporal lobe on both Audition Sound Semicircular Canals hemispheres Temporal lobe on both Chemical substances in Olfaction Olfactory cells hemispheres and Gaseous state Occipital lobe Chemical substances in Gustation Papillae (taste buds) Frontal lobe liquid state Meissner’s Corpuscle & Merkel’s Disks – pressure Pressure, Pain, Somatosenation Pacinian Corpuscle – vibration Parietal lobe Temperature Ruffini endings – warmth Krause’s Corpuscle - cold 3 3 Nervous System Neurons – basic, fundamental unit of the nervous system Cell body – houses the nucleus and other organelles Dendrites – root-like structures that receive information Axons – long fibers, conducts information away from the cell 4 4 2  05/09/2024 Neuron Myelin Sheath – insulation of axons Nodes of Ranvier – gaps in the insulation, unmyelinated part of the axon; speeds up the propoagation Neurofibrils – fibers within the axon 5 5 Types of Neurons Sensory/Afferent – receives information from the different sense organs / receptors in the body; from internal organs to CNS Interneuron – connects or integrates information coming from sensory and motor neurons; determines where information will be sent Motor/Efferent – from CNS to internal organs; responds to signals; homeostasis 6 6 3  05/09/2024 Axon Terminal 7 7 Action Potential 8 8 4  05/09/2024 Resting / Action Potential Tells about what happens when a neuron is at rest… When a neuron is not sending a signal, it is at rest… When a neuron is at rest, its inside is negative relative to the outside… At rest, K+ ions can cross the membrane; Na+ has a difficult time crossing… 9 9 The resulting Wave of Sodium ions Potassium Neuron action potential action Threshold diffuse ions diffuse membrane Sodium Potassium causes a local potentials stimulus inward, outward, maintains channels channels bioelectric travel the is depolarizing repolarizing resting open open current that length of the received the the potential stimulates the axon as a membrane membrane membrane nerve impulse 10 10 5  05/09/2024 Synapse Junction between two communicating neurons… To complete the signal, a neurotransmitter is released at the gap to signal the next neuron… Receptors on the next dendrite will receive the neurotransmitters… 11 11 Nervous System 12 12 6  05/09/2024 Divisions of the Nervous System 13 13 Divisions of the Nervous System Central Nervous System (CNS) Brain Spinal Cord Peripheral Nervous System (PNS) Cranial Nerves (12 pairs) Spinal Nerves (31 pairs) 14 14 7  05/09/2024 Central Nervous System 15 15 Brain Forebrain, Midbrain, Hindbrain (TeDiMesMetMy) Telencephalon Diencephalon Mesencephalon (midbrain) Metencephalon Myelencephalon 16 16 8  05/09/2024 Telencephalon Largest division; mediates the brain’s complex functions Initiates voluntary movement, interprets sensory input, mediates complex cognitive processes (learning, speaking, problem solving) Cerebral cortex – cerebrum; convoluted Fissures – deep, large furrows; Sulcus – shallow, small furrows Longitudinal fissure – separating the cerebral hemispheres Cerebral commissure – hemisphere connecting tracts; Corpus Callosum Lateral & central fissure – divides each hemisphere into lobes; tempo-parietal Transverse fissure – occipital - cerebellum Gyrus – bumps/ridges between fissures and sulci precentral, postcentral, superior temporal 17 17 Cerebrum (Telencephalon) Incorrect to think that a lobe is a functional unit, having one set of functions Frontal lobe – precentral: motor; prefrontal: cognition (planning response sequences, evaluating the outcomes of potential patterns of behavior and assessing significance of the behavior of others Parietal Lobe – postcentral gyrus: sensation from the body (touch), posterior: perceiving the location of both objects and our bodies and in directing our attention Temporal Lobe – superior: hearing and language, inferior: complex visual patterns, medial: certain kinds of memory Occipital Lobe – analysis of visual inputs 18 18 9  05/09/2024 Hippocampus (Telencephalon) Sea horse Major role in memories; spatial location 19 19 20 20 10  05/09/2024 Diencephalon Thalamus - top of the brain stem; comprised different pairs of nuclei sensory nuclei - receives signals from sensory receptors, process them transmit them to the appropriate areas of sensory cortex lateral geniculate nuclei – visual medial geniculate nuclei - auditory ventral posterior - somatosensory Hypothalamus – regulation of several motivated behaviors (eating, sleep and sexual behavior; regulates the release of hormones from the pituitary gland (snot gland) optic chiasm – point at which optic nerves from each eye come together mamillary bodies – part of the hypothalamus 21 21 22 22 11  05/09/2024 23 23 Mesencephalon Tectum – roof or dorsal surface of the midbrain; two pairs of bumps – colliculi (little hills) inferior colliculi – auditory function superior colliculi – visual-motor function; directing the body’s orientation toward or away from a particular visual stimuli Tegmentum – reticular formation; contains periaqueductal gray: connects 3rd and 4th ventricles; pain reduction effects of opioids, substantia nigra and red nucleus; both are for sensorimotor system 24 24 12  05/09/2024 Metencephalon Reticular formation – a bulge Pons – sleep (REM), respiration, swallowing, bladder control Cerebellum – sensorimotor structure, controls movement, adapt to changing conditions; not restricted to sensorimotor control 25 25 26 26 13  05/09/2024 Myelencephalon Medulla – carry the signals between the rest of the brain and the body Reticular formation – complex networks of nuclei that occupies the central core of the brain stem; arousal, sleep, attention, movement, maintenance of muscle tone, cardiac circulatory and respiratory reflexes 27 27 Limbic System and Basal Ganglia Limbic System Basal Ganglia Midline structures that circle the Voluntary motor responses and thalamus (limbic – ring) decision making Regulation of 4 Fs: Fleeing, Feeding, Fighting, Sexual Caudate – tail-like Behavior Putamen Globus pallidus – pale globe Amygdala – memories with emotional events; fear & aggression Cingulate cortex – receives input from thalamus; exec control Fornix - memory 28 28 14  05/09/2024 29 29 Peripheral Nervous System 30 30 15  05/09/2024 Somatic Nervous System – skeletal ; voluntary motor functions Autonomic Nervous System – smooth muscles; glands; involuntary Sympathetic NS (Fight/Flight) Parasympathetic NS (Rest/Digest) 31 31 32 32 16  05/09/2024 Spinal Cord ASCENDING - impulses travel to the brain (sensory) DESCENDING - impulses travel to the muscles (motor) 33 33 Spinal Nerves Nerves are numbered based on their location C1-C8 T1-T12 L1-L5 S1-S5 34 34 17  05/09/2024 35 35 Cranial Nerves 36 36 18  05/09/2024 Number Name Function I Olfactory nerves These nerves help produce the sense of smell. II Optic nerves These nerves transmit visual information from the retina of the eye to the brain. III Oculomotor nerves These nerves control the movement of the eye muscles, focusing of the eyes, and constricting of the pupils. IV Trochlear nerves These nerves work with the oculomotor nerves to help move the eye in different directions. These nerves extend from the pons to the face and assist with the sensations of touch, temperature, and pain. They transmit V Trigeminal information to the skin of the head, the eyelids, nose, teeth, lids, and inside of the mouth. VI Abducens These nerves come from the pons and help with eye movement. These nerves also arise from the pons and then innervate the face. They help send signals that stimulate chewing, saliva VII Facial production, and the taste buds. These nerves come from the cochlea and vestibule (the parts of the ear that control hearing and balance) in the inner ear. VIII Vestibulocochlear They assist the body in maintaining equilibrium and also help with hearing. These nerves come from the medulla oblongata and leave the skull to innervate the throat area. They help with the IX Glossopharyngeal movement of the throat and tongue muscles, allowing for swallowing to occur. They also help with the production of taste and the feelings of touch, pressure, and pain in the throat area. These nerves arise from the medulla oblongata and travel to areas of the body below the head and neck region. They X Vagus help provide signals to the heart, lungs, and abdominal cavity. They also carry signals to and from the skin, the taste buds, and the muscles of the larynx and pharynx. These nerves are unique in that they arise from the spinal cord, not the brain stem. They enter the skull at its base and XI Accessory travel with the vagus nerves to innervate two large neck muscles. They assist with motor functions of the trapezius and sternocleidomastoid muscles of the head and neck. These nerves come from the medulla oblongata and innervate the tongue. They allow for movements of the tongue when XII Hypoglossal chewing and swallowing. They also assist with speech. 37 37 Endocrine System 38 38 19  05/09/2024 Endocrine System ✘ A chemical communication network that sends messages throughout the body via the bloodstream ✘ Secrete hormones – chemical messengers ✘ Key component – pituitary gland (“master gland”) 39 39 Gland Hormone Effect on the Body - Releasing hormones (e.g., TRH, Regulate the pituitary gland’s hormone Hypothalamus CRH) release. - Growth hormone (GH) Stimulates growth and cell reproduction. Stimulates the thyroid gland to produce - Thyroid-stimulating hormone (TSH) thyroid hormones. Regulates testosterone production in - Luteinizing hormone (LH) males and ovulation in females. Pituitary Gland - Follicle-stimulating hormone (FSH) Stimulates egg and sperm production. - Prolactin (PRL) Stimulates milk production in females. - Antidiuretic hormone (ADH) - Antidiuretic hormone (ADH) Stimulates uterine contractions during - Oxytocin childbirth and milk ejection. 40 40 20  05/09/2024 Gland Hormone Effect on the Body Regulates metabolism, growth, and - Thyroxine (T4) development. Same as T4, but more potent and acts Thyroid Gland - Triiodothyronine (T3) faster. Lowers blood calcium levels by - Calcitonin promoting calcium storage in bones. Raises blood calcium levels by Parathyroid Glands - Parathyroid hormone (PTH) stimulating bone resorption. Regulates metabolism, stress response, - Cortisol and immune function. Regulates sodium and potassium - Aldosterone balance, and blood pressure. Adrenal Glands Increases heart rate, blood pressure, and - Epinephrine (adrenaline) energy supply in stress. Similar to epinephrine; affects attention - Norepinephrine and responding to stress. 41 41 Gland Hormone Effect on the Body Lowers blood glucose levels by Pancreas - Insulin facilitating cellular glucose uptake. Raises blood glucose levels by - Glucagon stimulating glucose release from the liver. Regulates female reproductive functions Ovaries - Estrogen and secondary sexual characteristics. Prepares the uterus for pregnancy and - Progesterone regulates the menstrual cycle. Regulates male reproductive functions Testes - Testosterone and secondary sexual characteristics. Regulates sleep-wake cycles and Pineal Gland - Melatonin seasonal biological rhythms. 42 42 21