Big Ideas. (e.g. puberty, immune function (autoimmune disorders)) 2011 Pearson Education, Inc.

Nervous Systems

Big Ideas 2.E.1: Timing and coordination of specific events are necessary for the normal development of an organism, and these events are regulated by a variety of mechanisms. (e.g. puberty, immune function (autoimmune disorders)) 2011 Pearson Education, Inc.

Big Ideas 3.E.1: Individuals can act on information and communicate it to others. Organisms exchange information with each other in response to internal changes and external cues, which change behavior. (e.g. fight or flight response; Fig. 49. 8) 3.E.2 d): Animals have nervous systems that detect external and internal signals, transmit and integrate information and produce responses. Different regions of the vertebrate brain have different functions. (e.g. vision, hearing) 2011 Pearson Education, Inc.

Big Ideas 3.E.1: Individuals can act on information and communicate it to others. Organisms exchange information with each other in response to internal changes and external cues, which change behavior. (e.g. fight or flight response) 3.E.2 d): Animals have nervous systems that detect external and internal signals, transmit and integrate information and produce responses. Different regions of the vertebrate brain have different functions. (e.g. vision, hearing) 2011 Pearson Education, Inc.

Big Ideas 4.A.3: Interaction between external stimuli and regulated gene expression result in specialization of cells, tissues, and organs. (e.g. signal transduction) 4.A.4 a): Organisms exhibit complex properties due to interactions between their constituent parts skeletal/nervous systems) (e.g. muscle & 4.A.4 b): Interactions and coordination between systems provide essential biological activities (e.g. sensory/motor) 4.B.2 a.2): Within multicellular organisms, specialization of organs contributes to the overall functioning of the organism (e.g. communication & control) 2011 Pearson Education, Inc.

Big Ideas 4.A.3: Interaction between external stimuli and regulated gene expression result in specialization of cells, tissues, and organs. 4.A.4 a): Organisms exhibit complex properties due to interactions between their constituent parts (e.g. muscle & skeletal/nervous systems) 4.A.4 b): Interactions and coordination between systems provide essential biological activities (e.g. sensory/motor) 4.B.2 a.2): Within multicellular organisms, specialization of organs contributes to the overall functioning of the organism (e.g. communication & control) 2011 Pearson Education, Inc.

Big Ideas 4.A.3: Interaction between external stimuli and regulated gene expression result in specialization of cells, tissues, and organs. 4.A.4 a): Organisms exhibit complex properties due to interactions between their constituent parts skeletal/nervous systems) (e.g. muscle & 4.A.4 b): Interactions and coordination between systems provide essential biological activities (e.g. sensory/motor) 4.B.2 a.2): Within multicellular organisms, specialization of organs contributes to the overall functioning of the organism (e.g. communication & control) 2011 Pearson Education, Inc.

AP Exam 2007 (#2)

Overview: Command and Control Center The human brain contains about 100 billion neurons, organized into circuits more complex than the most powerful supercomputers A recent advance in brain exploration involves a method for expressing combinations of colored proteins in brain cells, a technique called brainbow This may allow researchers to develop detailed maps of information transfer between regions of the brain 2011 Pearson Education, Inc.

Figure 49.1

Key Points Nervous systems consist of circuits of neurons and supporting cells. The vertebrate brain is regionally specialized. The cerebral cortex controls voluntary movement and cognitive functions.

Nervous systems consist of circuits of neurons and supporting cells Each single-celled organism can respond to stimuli in its environment Animals are multicellular and most groups respond to stimuli using systems of neurons 2011 Pearson Education, Inc.

Figure 49.2 Nerve net Radial nerve Nerve ring Eyespot Brain Nerve cords Transverse nerve Brain Ventral nerve cord Segmental ganglia (a) Hydra (cnidarian) (b) Sea star (echinoderm) (c) Planarian (flatworm) (d) Leech (annelid) Brain Brain Ventral nerve cord Segmental ganglia Anterior nerve ring Longitudinal nerve cords Ganglia Brain Ganglia Spinal cord (dorsal nerve cord) Sensory ganglia (e) Insect (arthropod) (f) Chiton (mollusc) (g) Squid (mollusc) (h) Salamander (vertebrate)

The simplest animals with nervous systems, the cnidarians, have neurons arranged in nerve nets A nerve net is a series of interconnected nerve cells More complex animals have nerves 2011 Pearson Education, Inc.

Nerves are bundles that consist of the axons of multiple nerve cells Sea stars have a nerve net in each arm connected by radial nerves to a central nerve ring 2011 Pearson Education, Inc.

Figure 49.2a Radial nerve Nerve net Nerve ring (a) Hydra (cnidarian) (b) Sea star (echinoderm)

Bilaterally symmetrical animals exhibit cephalization, the clustering of sensory organs at the front end of the body Relatively simple cephalized animals, such as flatworms, have a central nervous system (CNS) The CNS consists of a brain and longitudinal nerve cords 2011 Pearson Education, Inc.

Figure 49.2b Eyespot Brain Nerve cords Transverse nerve First cephalized animal Brain Ventral nerve cord Segmental ganglia (c) Planarian (flatworm) (d) Leech (annelid)

Ganglia Brain Ventral nerve cord Segmental ganglia Anterior nerve ring Longitudinal nerve cords (e) Insect (arthropod) (f) Chiton (mollusc)

Nervous system organization usually correlates with lifestyle Sessile molluscs (e.g. clams and chitons) have simple systems. More complex and motile molluscs (e.g. octopuses and squids) have more sophisticated systems. 2011 Pearson Education, Inc.

In vertebrates Figure 49.2d The CNS is composed of the brain and spinal cord The peripheral nervous system (PNS) is composed of nerves and ganglia Brain Brain Ganglia Spinal cord (dorsal nerve cord) Sensory ganglia (g) Squid (mollusc) (h) Salamander (vertebrate) 2011 Pearson Education, Inc.

Organization of the Vertebrate Nervous System The spinal cord conveys information from and to the brain The spinal cord also produces reflexes independently of the brain A reflex is the body s automatic response to a stimulus For example, a doctor uses a mallet to trigger a knee-jerk reflex 2011 Pearson Education, Inc.

Figure 49.3 Quadriceps muscle Cell body of sensory neuron in dorsal root ganglion Gray matter White matter Hamstring muscle Spinal cord (cross section) Sensory neuron Motor neuron Interneuron

Differing nerve cords Invertebrates Invertebrates usually have a ventral nerve cord Vertebrates Vertebrates have a dorsal spinal cord The spinal cord and brain develop from the embryonic nerve cord The nerve cord gives rise to the central canal and ventricles of the brain 2011 Pearson Education, Inc.

Figure 49.4 Central nervous system (CNS) Brain Spinal cord Peripheral nervous system (PNS) Cranial nerves Ganglia outside CNS Spinal nerves

The central canal of the spinal cord and the ventricles of the brain are hollow and filled with cerebrospinal fluid (CSF) The cerebrospinal fluid is filtered from blood and functions to cushion the brain and spinal cord as well as to provide nutrients and remove wastes 2011 Pearson Education, Inc.

Figure 49.5 Gray matter White matter Ventricles

50 m Figure 49.6 VENTRICLE Cilia CNS Neuron Astrocyte PNS Oligodendrocyte Schwann cell Microglial cell Capillary Ependymal cell LM

The Peripheral Nervous System Input Process (CNS) Output

The Peripheral Nervous System (PNS) The PNS transmits information to and from the CNS and regulates movement and the internal environment afferent neurons transmit information to the CNS efferent neurons transmit information away from the CNS

The PNS has two efferent components: Motor System The motor system carries signals to skeletal muscles and is voluntary Autonomic System The autonomic nervous system regulates smooth and cardiac muscles and is generally involuntary 2011 Pearson Education, Inc.

Figure 49.7 Central Nervous System (information processing) Peripheral Nervous System Afferent neurons Efferent neurons Sensory receptors Autonomic nervous system Motor system Control of skeletal muscle Internal and external stimuli Sympathetic division Parasympathetic division Control of smooth muscles, cardiac muscles, glands Enteric division

The sympathetic regulates arousal and energy generation ( fight-or-flight response) The parasympathetic system has antagonistic effects on target organs and promotes calming and a return to baseline ( rest and digest ) functions 2011 Pearson Education, Inc.

Figure 49.8a Parasympathetic division Action on target organs: Constricts pupil of eye Stimulates salivary gland secretion Constricts bronchi in lungs Slows heart Stimulates activity of stomach and intestines Stimulates activity of pancreas Cervical Sympathetic ganglia Sympathetic division Action on target organs: Dilates pupil of eye Inhibits salivary gland secretion Stimulates gallbladder

Figure 49.8b Parasympathetic division Sympathetic division Relaxes bronchi in lungs Accelerates heart Thoracic Lumbar Inhibits activity of stomach and intestines Inhibits activity of pancreas Stimulates glucose release from liver; inhibits gallbladder Stimulates adrenal medulla Promotes emptying of bladder Inhibits emptying of bladder Promotes erection of genitalia Synapse Sacral Promotes ejaculation and vaginal contractions

Figure 49.8 Parasympathetic division Sympathetic division Action on target organs: Action on target organs: Constricts pupil of eye Dilates pupil of eye Stimulates salivary gland secretion Inhibits salivary gland secretion Constricts bronchi in lungs Cervical Sympathetic ganglia Relaxes bronchi in lungs Slows heart Stimulates activity of stomach and intestines Stimulates activity of pancreas Stimulates gallbladder Promotes emptying of bladder Thoracic Lumbar Fight or Flight Rest & Digest Accelerates heart Inhibits activity of stomach and intestines Inhibits activity of pancreas Stimulates glucose release from liver; inhibits gallbladder Stimulates adrenal medulla Inhibits emptying of bladder Promotes erection of genitalia Synapse Sacral Promotes ejaculation and vaginal contractions

The enteric division controls activity of the digestive tract, pancreas, and gallbladder 2011 Pearson Education, Inc.

Key Points Cue TED talk @ 5:00. Nervous systems consist of circuits of neurons and supporting cells. The vertebrate brain is regionally specialized. The cerebral cortex controls voluntary movement and cognitive functions.

The vertebrate brain is regionally specialized Specific brain structures are particularly specialized for diverse functions These structures arise during embryonic development 2011 Pearson Education, Inc.

Figure 49.9a

Figure 49.9b Embryonic brain regions Brain structures in child and adult Forebrain Midbrain Telencephalon Diencephalon Mesencephalon Cerebrum (includes cerebral cortex, white matter, basal nuclei) Diencephalon (thalamus, hypothalamus, epithalamus) Midbrain (part of brainstem) Hindbrain Metencephalon Myelencephalon Pons (part of brainstem), cerebellum Medulla oblongata (part of brainstem) Midbrain Hindbrain Mesencephalon Cerebrum Metencephalon Diencephalon Myelencephalon Diencephalon Midbrain Pons Forebrain Telencephalon Spinal cord Medulla oblongata Cerebellum Spinal cord Embryo at 1 month Embryo at 5 weeks Child

The cerebral cortex controls voluntary movement and cognitive functions The cerebrum is the largest structure in the human brain. It is essential for: awareness, language, cognition, memory, and consciousness Four regions, or lobes, are landmarks for particular functions: frontal, temporal, occipital, and parietal 2011 Pearson Education, Inc.

Figure 49.15 Frontal lobe Prefrontal cortex (decision making, planning) Motor cortex (control of skeletal muscles) Somatosensory cortex (sense of touch) Parietal lobe Sensory association cortex (integration of sensory information) Broca s area (forming speech) Visual association cortex (combining images and object recognition) Temporal lobe Auditory cortex (hearing) Wernicke s area (comprehending language) Cerebellum Occipital lobe Visual cortex (processing visual stimuli and pattern recognition)

Language and Speech Studies of brain activity have mapped areas responsible for language and speech Broca s area in the frontal lobe is active when speech is generated Wernicke s area in the temporal lobe is active when speech is heard These areas belong to a larger network of regions involved in language 2011 Pearson Education, Inc.

Lateralization of Cortical Function The two hemispheres make distinct contributions to brain function The left hemisphere is more adept at: -language -math -logic -processing of serial sequences The right hemisphere is stronger at: -pattern recognition, -nonverbal thinking -emotional processing 2011 Pearson Education, Inc.