What’s Next in What’s Next in Biology Class? Biology Class?
Dec 26, 2015
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
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
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
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