What’s Next in Biology What’s Next in Biology Class?Class?

Optical Illusion 1Optical Illusion 1

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Human Body UnitHuman Body Unit

Chapter 35 – Chapter 35 – Introduction to body systems Introduction to body systems

and and Nervous SystemNervous System

OrganizationOrganizationCellsCells: basic structures of life that specialize to : basic structures of life that specialize to perform a functionperform a function

TissuesTissues: group of cells that performs certain : group of cells that performs certain functionfunction EpithelialEpithelial: glands and tissues that form linings: glands and tissues that form linings ConnectiveConnective: support for the body and connect parts: support for the body and connect parts NervousNervous: transmit nerve impulses: transmit nerve impulses MuscleMuscle: with bones, enables body to move: with bones, enables body to move

OrgansOrgans: groups of tissues working together for a : groups of tissues working together for a functionfunction

Organ systemsOrgan systems: Group of organs that perform : Group of organs that perform related functionsrelated functions

4 Types of Tissue4 Types of Tissue

Why?Why?

HomeostasisHomeostasis

Organisms need to keep internal conditionsOrganisms need to keep internal conditions

relatively constant despite changes in their relatively constant despite changes in their external environmentsexternal environments

35.1 Human Body Systems35.1 Human Body Systems(p892-893)(p892-893)

SystemSystem StructuresStructures FunctionFunctionNervousNervous

IntegumentaryIntegumentary

SkeletalSkeletal

MuscularMuscular

RespiratoryRespiratory

CirculatoryCirculatory

DigestiveDigestive

ExcretoryExcretory

EndocrineEndocrine

ReproductiveReproductive

Lymphatic/immuneLymphatic/immune

Nervous SystemNervous System

OrganizationOrganizationNerve cells are called neurons:Nerve cells are called neurons: Impulses are the electrical signals Impulses are the electrical signals

carried from neuron to neuron.carried from neuron to neuron. Dendrites branch to the cell body Dendrites branch to the cell body

and carry messages to other cells.and carry messages to other cells. Axons carry impulses away from Axons carry impulses away from

the cell body.the cell body. Synapses are the spaces between Synapses are the spaces between

2 neurons.2 neurons. The sodium potassium pump is the The sodium potassium pump is the

mechanism by which impulses are mechanism by which impulses are carried from cell to cellcarried from cell to cell

The Nerve ImpulseThe Nerve ImpulseA reversal of charges is created across cell A reversal of charges is created across cell membranes.membranes.

Resting potential is changed to action potential Resting potential is changed to action potential when an impulse from a neuron is stimulated when an impulse from a neuron is stimulated by another neuron or the environmentby another neuron or the environment

The threshold is the minimum required The threshold is the minimum required stimulus to produce an impulse.stimulus to produce an impulse.

Neurotransmitters are chemicals used by Neurotransmitters are chemicals used by neurons to transmit an impulse across neurons to transmit an impulse across synapses. synapses.

Organization (cont.)Organization (cont.)

Related neurons form nerves and Related neurons form nerves and collectively form the CNS and PNScollectively form the CNS and PNS Central nervous systemCentral nervous system

Spinal CordSpinal Cord

BrainBrain

Meninges and cerebrospinal fluid Meninges and cerebrospinal fluid protect the CNSprotect the CNS

Spinal CordSpinal Cord Sensory neurons carry Sensory neurons carry impulses from receptors impulses from receptors to the spinal cordto the spinal cord

Motor neurons carry Motor neurons carry impulses from the spinal impulses from the spinal cord to the effectorscord to the effectors

Association neurons Association neurons maintain neural maintain neural connections within the connections within the spinal cordspinal cord

BrainBrain

CerebrumCerebrum Largest portion that is further divided into Largest portion that is further divided into

hemispheres and then 4 lobeshemispheres and then 4 lobes Controls motor and sensory activitiesControls motor and sensory activities

CerebellumCerebellum Coordinates muscle activityCoordinates muscle activity

Brain stemBrain stem Connects cerebrum with the spinal cordConnects cerebrum with the spinal cord

Brain stemBrain stem

Midbrain: controls reflexesMidbrain: controls reflexesMedulla oblongata: nerve Medulla oblongata: nerve

relay station and control centerrelay station and control centerPons: relays messages between cerebrum Pons: relays messages between cerebrum and cerebellumand cerebellumThalamus: directs incoming sensory Thalamus: directs incoming sensory impulses (not smell)impulses (not smell)Hypothalamus: helps maintain chemical Hypothalamus: helps maintain chemical homeostasishomeostasis

Brain Brain StructureStructure

Brain tourBrain tour

QuizQuiz

Peripheral nervous systemPeripheral nervous systemSensory division: transmits impulses from Sensory division: transmits impulses from senses to CNSsenses to CNS

Motor division: transmits impulses from CNS to Motor division: transmits impulses from CNS to muscles or glandsmuscles or glands

Somatic NS: regulates activities that are under Somatic NS: regulates activities that are under conscious control. EX:conscious control. EX:

Autonomic NS: regulates involuntary activities. Autonomic NS: regulates involuntary activities. EX:EX: Sympathetic and parasympathetic nervous systems Sympathetic and parasympathetic nervous systems

work together to control homeostasiswork together to control homeostasis

Peripheral Nervous System

Somatic Nervous System

Autonomic Nervous System

Sympathetic(stress)Parasympathetic

(routine)