UNIT III LIVINGTHINGSANDTHEIRENVIRONMENT LESSON 5 Maintaining HOMEOSTASIS memory and stimulus and Maintaining HOMEOSTASIS Example: Regulating the core temperature of the body ➢ any self-regulating process by which an organism tends to maintain stability while adjusting to conditions that are best for its survival. Heat loss to the environment When bodytemperature is toohigh Blood vesselswill dilate 37˚ Celsius 98.6˚ Fahrenheit THERMOREGULATION Will trigger sweat glands To produce sweat to evaporates and cools the body What will happen if the body temperature is nor regulated? hyperthermia Abnormal high body temperature hypothermia Dangerous drop in the body temperature ORGAN FAILURE HOMEOSTASIS Bloodsugar regulation INSULIN High blood glucose level Blood pressure regulation (hormone) ANGIOSTENSIN (hormone) High blood pressure Defendingagainst pathogenic bacteria and viruses Bloodstream Pathogens enters the body LYMPHOCYTES (white blood cells) Controls blood vessel dilation Phagocytosis and Change in the environment Fly movingtowards our eyes Reaction in the sudden change sense as threat Automatically blink to avoid damage BRAIN ➢ Command center of the entire body ➢ It process information gathered by sensory receptors and responds by sending nerve impulses to the motor nerves ➢ Primarily controls: Intelligence Sensory Motor Activity SPINALCORD The most complex organ of body the controls and coordinates ACTION& REACTION THINKING EMOTIONS MEMORY Protected and encased by the bone of the head: Cranial cavity Surrounded with fluid called: ➢ Cushions the brain against sudden impact Associated with mathematical and logical ability SPEECH Associated with artistic ability CREATIVITY COMPREHENSION SPATIALABILITY ARITHMETIC WRITING MUSICALSKILLS Thick bundle of nerve fibers that bridges the two hemisphere ensuring both sides can communicate and send signals to each other CEREBRUM CEREBELLUM BRAIN STEM ➢ Largest part of the brain (85% of the size) Gyri & sulci CEREBRALCORTEX ➢ Surface of the cerebrum where learning and judgment occurs. ➢ Folds on the surface of the brain ➢ Also controls all voluntary activities of the body, emotions and personality. GYRI & SULCI ➢ Gyri provide the increased surface area and house the brain's functional regions, while sulci help organize the brain into distinct lobes and protect it from injury. The combination of these structures allows the brain to perform its intricate functions and process a wide range of sensory and cognitive information. FRONTAL LOBE ➢ personality PARIETAL LOBE Interprets sensory input such as: ➢ judgment ➢ touch ➢ reasoning ➢ pain ➢ language expression ➢ temperature ➢ voluntary movement TEMPORAL LOBE ➢ memory ➢ speech ➢ Perception and recognition of auditory stimulus OCCIPITAL LOBE ➢ Interprets visual stimulus from our surroundings ➢ Second largest part of the brain ➢ Provides instruction for coordination of skeletal muscle movements, proper balance and posture. ➢ Connects the brain and the spinal cord Medulla Oblongata BRAIN STEM ➢ Responsible for the eye reflexes: Coordination of eye movement Dilation of the pupil in response to brightness BRAIN STEM ➢ Connects the cerebrum and cerebellum and involves in the regulation of: Respiration Saliva secretion Chewing and tasting Facial expressions BRAIN STEM ➢ Controls involuntary actions such as: HEARTBEAT BREATHING BLOODPRESSURE ➢ Relays motor and sensory signals to the cerebral cortex. ➢ Regulation body temperature ➢ Controls the production of hormones ➢ Controls sleep and waking cycle ➢ Long , thin masses of bundled neurons which channels signals (nerve impulses) to and from the brain Enclosed by the: VERTEBRALCOLUMN (Spinal column) ➢ Is an involuntary reaction in response to stimulus transmitted to the CNS ➢ It allows an individual to react to a stimulus more quickly, without any brain involvement, to ensure protection of the body from an injury. ➢ Most reflex doesn’t involve the higher brain centers, most it involves: BRAINSTEM SPINALCORD Is a pathway of neurons that carries nerve impulses for an automatic response FIVE BASIC COMPONENTS SENSORY RECEPTOR SENSORY NEURON ASSOCIATION NEURON MOTOR NEURON EFFECTOR ORGAN KNEE-JERKREACTION KNEE-JERK REFLEX ARC (SPINAL REFLEX) 2.SENSORY NEURON 1. SENSORY RECEPTOR: SKIN (KNEE) SPINAL CORD 3.INTERNEURON ( 4. MOTOR NEURON 5. EFFFECTOR ORGAN: MUSCLE (KNEE) ➢ Links the central nervous system to the rest of the body ➢ It gathers and delivers information to and from the central nervous system. PNS ➢ Made up of network of nerves which extends from the CNSto the different parts of the body Compose of 2 cells NEURONS NEUROGLIA ➢ Are the basic functional and structural unit of the nervous system ➢ They carry information through the nervous system in the form of nerve impulse. ➢ Neurons receives stimuli and transmit impulses to other neurons or to other body organs p DENDRITES (AFFERENT PROCESS) ➢ Branching structures that receives signals from other neurons and carries towards the cell body CELL BODY ➢ Integrates incoming signals from dendrites and generates outgoing signals to the axon. AXON (EFFERENT PROCESS) ➢ Carries impulse away from the cell body MYELIN SHEATH ➢ Speeds up the travel of electrical impulses through the axons. AXON TERMINAL ➢ Pass on impulses to the dendrites of other neurons. SENSORY NEURONS Carry sensory impulses (stimuli) from receptors to the spinal cord or to the brain MOTOR NEURONS Carry motor impulses from the brain or spinal cord to the target muscle ASSOCIATIVE NEURONS (INTERNEURONS) Connects sensory neurons and motor neurons SENSORY NEURONS SENSORY INPUT Nerve impulse begin when receptors from sense organs (eyes) pick up stimulus from the environment, which triggers nerve impulses in the sensory neurons INTERNEURONS Nerve impulse travel to the interneurons in the brain. The brain interprets from the many interneurons that you are attached to something on the screen. It decides that you touch the area that interest you INTEGRATION MOTOR NEURONS MOTOR INPUT Nerve impulse travel to the motor neurons that send impulses to the muscles. The appropriate response is to use your finger to point and touch an area on the screen Neurons do not touch one another as they transfer nerve impulses Nerve impulses (chemical signals) jump through a gap between two neurons called: Contact between two neurons (GLIAL CELLS) ➢ a non-conducting cells that provides support and protection to neurons. TYPES ASTROCYTES Supply nutrients to the neurons EPENDYMAL CELLS Produce the cerebrospinal fluid MICROGLIAL CELLS Helps in removing debris and bacteria OLIGODENDROCYTES Produce the myelin sheath for insulation of axon in CNS SCHWANN CELLS Produce the myelin sheath for insulation of axon in PNS SOMATIC NERVOUS SYSTEM (SNS) Controls voluntary muscles SKELETAL MUSCLES AUTONOMIC NERVOUS SYSTEM (ANS) Controls involuntary muscles SMOOTH MUSCLES CARDIAC MUSCLES SUBDIVISIONS SYMPATHETIC NERVOUS SYSTEM PARASYMPATHETIC NERVOUS SYSTEM ➢ Activated in times of physical and emotional stress or whenever the body requires some action. FIGHT or FLIGHT RESPONSE VERYANGRY VERY NERVOUS FRIGHTENED INCREASING HEART RATE INCREASING BLOOD PRESSURE PERSPIRATION ➢ It acts opposite to the function of the sympathetic nervous system by calming the body, conserving energy and returning body functions to normal level. DECREASES HEART RATE & BLOOD PRESSURE ➢ It stimulates vegetative activities and most active under normal condition. BREATHING DIGESTION DEFECATION & URINATION ➢ Inflammation of the brain tissues caused by infection HERPES SIMPLEX VIRUS ENTEROVIRUS TRANSMISSION: Bite of an infected blood sucking insects: MOSQUITO TICKS ➢ Inflammation of the membranes surrounding the brain and spinal cord caused by viral or bacterial infection MENINGOCOCCAL BACTERIA ENTEROVIRUS TRANSMISSION: Direct contact with body fluids through: SNEEZING COUGHING ➢ Aprogressive disease that affects the patients movement. ➢ It occurs when the nerve cell in the brain called: “substantia nigra” that produces neurotransmitters become impaired or die. ➢ This phenomenon impairs the motor skills and other functions resulting in tremors and slowing or loss of physical movement. ➢ Characterized by sever mental deterioration which gets worse over time. ➢ Decrease in the brain size, which results from degeneration of brain cells, causing a decline in memory and mental function. CAUSE: ➢ Brain proteins fails to function properly, damaging neurons and eventually die ➢ The loss of neurons spreads to different areas causingthe brain to shrunk.
