CELLS

Adipose Tissue

BONE CELLS Osteocytes

CARTILAGE

MUSCLE CELLS

NERVE CELLS (NEURONS)

CELLS FROM THE EYE

SKIN CELLS (EPITHELIAL)

CELLS FROM MOUTH

TOOTH

NASAL CELLS

CELLS OF LUNG

LIVER CELLS (hepatocytes)

Nervous systems Nervous systems contain neural cells and glial cells

Types of neurons Sensory neurons Interneurons Motor neurons

Sensory receptor Sensory neuron Brain Motor Spinal neuron cord Fig. 28-1b 1 Sensory receptor 2 Sensory neuron Brain Motor neuron Spinal cord 3 4 Quadriceps muscles Interneuron CNS Nerve Flexor muscles PNS

Signal direction Dendrites Cell Body Cell body Layers of Fig. 28-2 Signal direction Dendrites Cell Body Cell body Layers of myelin sheaths Signal pathway Schwann cell Nucleus Axon Nucleus Schwann cell Myelin sheath Synaptic terminals

Neurons work by sending an electrical impulse (action potential) from one end of the neuron (cell body) to the other (synaptic terminal)

-inside is negative; outside is positive Resting Potential There is a difference in the distribution of charges inside the cell compared to outside -inside is negative; outside is positive There is a difference in the concentration of certain ions inside compared to outside outside high concentration of Na+ inside high K+ Animation link

Action Potential A stimulus to a neuron causes Na+ gates to open (Na+ rushes into the cell) reversing the charge cell is DEPOLARIZED Charge distribution is reestablished when K+ is allowed to leave the cell Cell is Repolarized Na+/K+ pump reestablishes the ion concentrations (expends the most energy in your body)

Sending the message on

Synaptic terminals Inhibitory Dendrites Excitatory Myelin sheath Fig. 28-7a Synaptic terminals Dendrites Inhibitory Excitatory Myelin sheath Receiving cell body Axon

Fig. 28-7b Synaptic terminals

Acetylcholine motor neurons / muscles Serotonin & dopamine in brain affect sleep/mood Botulinum toxin -inhibits release of acetylcholine

Sending neuron Action potential arrives Vesicles Axon of sending 1 Action potential arrives Vesicles Axon of sending neuron Synaptic terminal Synapse 2 3 Vesicle fuses with plasma membrane Neurotransmitter is released into synaptic cleft Figure 28.6 Neuron communication. Synaptic cleft Receiving neuron 4 Neurotransmitter binds to receptor Receiving neuron Neurotransmitter molecules Ion channels

Neurotransmitter broken down and released Receptor Ions Figure 28.6 Neuron communication. . 5 Ion channel opens 6 Ion channel closes

Fetus (three months old) Cerebral hemisphere Diencephalon Midbrain Midbrain Hindbrain Pons Cerebellum Medulla oblongata Figure 28.14 Embryonic development of the human brain. Spinal cord Forebrain Embryo (one month old) Fetus (three months old)

Cerebral cortex Cerebrum Thalamus Forebrain Hypothalamus Pituitary gland Figure 28.15A The main parts of the human brain. Midbrain Pons Spinal cord Medulla oblongata Hindbrain Cerebellum

Left cerebral hemisphere Right cerebral hemisphere Corpus callosum Figure 28.15B A rear view of the brain. Corpus callosum Basal ganglia

Frontal lobe Parietal lobe Somatosensory cortex Motor cortex association area Frontal association area Speech Taste Reading Speech Hearing Visual association area Smell Figure 28.16 Functional areas of the left cerebral hemisphere. Auditory association area Vision Temporal lobe Occipital lobe

Embryonic Brain Regions Brain Structures Present in Adult Cerebrum (cerebral hemispheres; includes cerebral cortex, white matter, basal ganglia) Forebrain Diencephalon (thalamus, hypothalamus, posterior pituitary, pineal gland) Midbrain Midbrain (part of brainstem) Figure 28.14 Embryonic development of the human brain. Pons (part of brainstem), cerebellum Hindbrain Medulla oblongata (part of brainstem)

Sensory receptors Specialized cells or neurons that detect stimuli Sensory receptors Specialized cells or neurons that detect stimuli Student Misconceptions and Concerns 1. The concept of sensory transduction, as applied to any particular sense organ, is typically new to most students. Students’ familiarity with numerous forms of digital technology may help them make a connection. CD players, DVD recordings, and MP3 players rely upon electricity and signal conversions to store and generate sounds and images. Teaching Tips 1. Students can better understand sensory adaptation by thinking about events in their lives. Perhaps they have visited a grandparent’s home and noticed a distinct smell, possibly that of freshly baked items. Maybe they have entered a science building and picked up a few distinct odors! However, after a few minutes, we tend not to notice the smells as much. These experiences illustrate sensory adaptation.

Peripheral nervous system Somatic nervous system Autonomic nervous Fig. 28-12 Peripheral nervous system Somatic nervous system Autonomic nervous system Sympathetic division Parasympathetic division Enteric division

Fig. 28-13 Parasympathetic division Sympathetic division Brain Eye Constricts pupil Dilates pupil Salivary glands Stimulates saliva production Inhibits saliva production Lung Constricts bronchi Dilates bronchi Accelerates heart Slows heart Heart Adrenal gland Spinal cord Stimulates epinephrine and norepi- nephrine release Liver Stomach Stimulates stomach, pancreas, and intestines Pancreas Stimulates glucose release Inhibits stomach, pancreas, and intestines Intestines Bladder Stimulates urination Inhibits urination Promotes erection of genitals Promotes ejacu- lation and vaginal contractions Genitalia

All senses trigger the same type of action potential All senses trigger the same type of action potential The brain distinguishes the type of stimulus Perception is the brain’s integration of sensations Teaching Tips 1. Optical illusions can reveal the mental gymnastics our mind performs to make sense of our visual world. Consider searching “optical illusions” on the Internet to identify some examples to share with your class. Copyright © 2009 Pearson Education, Inc.

The hypothalamus “master controller” influences many hormones The hypothalamus Links the endocrine and nervous systems Receives input from nerves about body conditions Responds by sending out appropriate nervous or endocrine signals Uses the pituitary gland to exert master control over the endocrine system Student Misconceptions and Concerns 1. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. Although this is mentioned briefly in the text, consider emphasizing further the potential negative consequences of the abuse of these powerful hormones. The National Institutes of Health provide additional details on its website at www.drugabuse.gov/ResearchReports/Steroids/AnabolicSteroids.html. Teaching Tips 1. Morphine and other opiates bind to the same cell receptors that naturally bind endorphins, producing powerful pain-killing effects. Copyright © 2009 Pearson Education, Inc.

The pituitary gland Brain Hypothalamus Posterior pituitary Figure 26.4A Location of the hypothalamus and pituitary. Anterior pituitary (Bone)

Uterine muscles Mammary glands Hypothalamus Hormone Neuron cell Posterior pituitary Anterior pituitary Blood vessel Figure 26.4B Hormones of the posterior pituitary. Oxytocin ADH Uterine muscles Mammary glands Kidney tubules

the anterior pituitary Neuron cell Blood vessel Releasing hormones from hypothalamus Endocrine cells of the anterior pituitary Figure 26.4C Hormones of the anterior pituitary. Pituitary hormones TSH ACTH FSH and LH Prolactin (PRL) Growth hormone (GH) Endorphins Thyroid Adrenal cortex Testes or ovaries Mammary glands (in mammals) Entire body Pain receptors in the brain

HORMONES AND HOMEOSTASIS HORMONES AND HOMEOSTASIS Copyright © 2009 Pearson Education, Inc.

Feedback Inhibition Hypothalamus Inhibition TRH The product of a pathway shuts down an earlier step in the pathway Anterior pituitary Inhibition TSH Thyroid Thyroxine

Pancreatic hormones regulate blood glucose levels The pancreas secretes two hormones that control blood glucose Insulin—signals cells to use and store glucose Glucagon—causes cells to release stored glucose into the blood Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. 2. As the section title indicates, a central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. Teaching Tips 1. The use of calcitonin and parathyroid hormone to hold blood calcium levels steady is similar to the use of a heater and chiller on a fish tank or a laboratory incubator to hold temperatures steady. The same analogy can be applied to the contrasting functions of insulin and glucagon. 2. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is http://diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/. Copyright © 2009 Pearson Education, Inc.

Homeostasis: Normal blood glucose level Body cells take up more glucose Insulin 3 2 Beta cells of pancreas stimulated to release insulin into the blood 4 Blood glucose level declines to a set point; stimulus for insulin release diminishes Liver takes up glucose and stores it as glycogen 1 High blood glucose level Stimulus: Rising blood glucose level (e.g., after eating a carbohydrate-rich meal) Glucose level Homeostasis: Normal blood glucose level (about 90 mg/100 mL) Stimulus: Declining blood glucose level (e.g., after skipping a meal) Glucose level Figure 26.7 Glucose homeostasis. 5 Low blood glucose level Blood glucose level rises to set point; stimulus for glucagon release diminishes 6 Alpha cells of pancreas stimulated to release glucagon into the blood 8 Liver breaks down glycogen and releases glucose to the blood 7 Glucagon

Homeostasis: Normal blood glucose level Body cells take up more glucose Insulin 3 2 Beta cells of pancreas stimulated to release insulin into the blood 4 Blood glucose level declines to a set point; stimulus for insulin release diminishes Liver takes up glucose and stores it as glycogen 1 High blood glucose level Stimulus: Rising blood glucose level (e.g., after eating a carbohydrate-rich meal) Figure 26.7 Glucose homeostasis. Glucose level Homeostasis: Normal blood glucose level (about 90 mg/100 mL) Glucose level

Homeostasis: Normal blood glucose level (about 90 mg/100 mL) Stimulus: Declining blood glucose level (e.g., after skipping a meal) Glucose level 5 Low blood glucose level Blood glucose level rises to set point; stimulus for glucagon release diminishes 6 Alpha cells of pancreas stimulated to release glucagon into the blood Figure 26.7 Glucose homeostasis. 8 Liver breaks down glycogen and releases glucose to the blood 7 Glucagon