When most people hear the term cardiovascular system, they immediately think of the heart. We have all felt our own heart "pound" from time to time, and we tend to get a bit nervous when this happens. The crucial importance of the heart has been recognized for a long time. However, the cardiovascular system is much more than just the heart, and from a scientific and medical standpoint, it is important to understand why this system is so vital to life.

Most simply stated, the major function of the cardiovascular system is transportation. Using blood as the transport vehicle, the system carries oxygen, nutrients, cell wastes, hormones, and many other substances vital for body homeostasis to and from the cells. The force to move the blood around the body is provided by the beating heart. The cardiovascular system can be compared to a muscular pump equipped with one-way valves and a system of large and small plumbing tubes within which the blood travels. Blood (the substance transported) is discussed in Chapter 10. Here we will consider the heart (the pump) and the blood vessels (the network of tubes).
Objective Checklist

Cardiovascular System: The Heart

• Describe the location of the heart in the body and identify its major anatomical areas on an appropriate model or diagram.
• Trace the pathway of blood through the heart.
• Compare the pulmonary and systemic circuits.
• Explain the operation of the heart valves.
• Name the functional blood supply of the heart.
• Name the elements of the intrinsic conduction system of the heart and describe the pathway of impulses through this system.
• Define systole, diastole, stroke volume, and cardiac cycle.
• Define heart sounds and murmur.
• Explain what information can be gained from an electrocardiogram.
• Describe the effect of the following on heart rate: stimulation by the vagus nerve, exercise, epinephrine, and various ions.

Cardiovascular System: Blood Vessels

• Compare and contrast the structure and function of arteries, veins, and capillaries.
• Identify the body's major arteries and veins and name the body region supplied by each.
• Discuss the unique features of special circulations of the body: arterial circulation of the brain, hepatic portal circulation, and fetal circulation.
• Define blood pressure and pulse and name several pulse points.
• List factors affecting and/or determining blood pressure.
• Define hypertension and atherosclerosis and describe possible health consequences of these conditions.
• Describe the exchanges that occur across capillary walls.

Developmental Aspects of the Cardiovascular System

• Describe briefly the development of the cardiovascular system.
• Name the fetal vascular modifications, or "fetal shunts," and describe their function before birth.
• Explain how regular exercise and a diet low in fats and cholesterol may help maintain cardiovascular health.

When insulin molecules, carried passively along in the blood, leave the blood and bind tightly to protein receptors of nearby cells, the response is dramatic: Bloodborne glucose molecules begin to disappear into the cells, and cellular activity accelerates. Such is the power of the second great controlling system of the body, the endocrine system. Along with the nervous system, it coordinates and directs the activity of the body's cells. However, the speed of control in these two great regulating systems is very different. The nervous system is "built for speed." It uses nerve impulses to prod the muscles and glands into immediate action so that rapid adjustments can be made in response to changes occurring both inside and outside the body. On the other hand, the more slowly acting endocrine system uses chemical messengers called hormones, which are released into the blood to be transported leisurely throughout the body.

Although hormones have widespread and varied effects, the major processes controlled by hormones are reproduction; growth and development; mobilizing body defenses against stressors; maintaining electrolyte, water, and nutrient balance of the blood; and regulating cellular metabolism and energy balance. As you can see, the endocrine system regulates processes that go on for relatively long periods and, in some cases, continuously.
Objective Checklist

The Endocrine System and Hormone Function: An Overview

• Define hormone and target organ.
• Describe how hormones bring about their effects in the body.
• Explain how various endocrine glands are stimulated to release their hormonal products.
• Define negative feedback and describe its role in regulating blood levels of the various hormones.

The Major Endocrine Organs

• Describe the difference between endocrine and exocrine glands.
• On an appropriate diagram, identify the major endocrine glands and tissues.
• List hormones produced by the endocrine glands and discuss their general functions.
• Discuss ways in which hormones promote body homeostasis by giving examples of hormonal actions.
• Describe the functional relationship between the hypothalamus and the pituitary gland.
• Describe major pathological consequences of hypersecretion and hyposecretion of the hormones considered in this chapter.

Other Hormone-Producing Tissues and Organs

• Indicate the endocrine role of the kidneys, the stomach and intestine, the heart, and the placenta.

Developmental Aspects of the Endocrine System

• Describe the effect of aging on the endocrine system and body homeostasis.

Special Senses

We are usually told that we have five senses that keep us in touch with what is going on in the external world: touch, taste, smell, sight, and hearing. Actually touch is a mixture of the general senses that we considered in Chapter 7-the temperature, pressure, and pain receptors of the skin and the proprioceptors of muscles and joints. The other four "traditional" senses-smell, taste, sight, and hearing-are called special senses. Receptors for a fifth special sense, equilibrium, are housed in the ear, along with the organ of hearing. In contrast to the small and widely distributed general receptors, the special sense receptors are either large, complex sensory organs (eyes and ears) or localized clusters of receptors (taste buds and olfactory epithelium).

This chapter focuses on the functional anatomy of each of the special sense organs individually, but keep in mind that sensory inputs are overlapping. What we finally experience-our "feel" of the world-is a blending of stimulus effects.
Objective Checklist

The Eye and Vision

• When provided with a model or diagram, identify the accessory eye structures and list the functions of each.
• Name the eye tunics and indicate the major function of each.
• Explain how rod and cone function differ.
• Describe image formation on the retina.
• Trace the pathway of light through the eye to the retina.
• Discuss the importance of an ophthalmoscopic examination.
• Define the following terms: accommodation, astigmatism, blind spot, cataract, emmetropia, glaucoma, hyperopia, myopia, and refraction.
• Trace the visual pathway to the optic cortex.
• Discuss the importance of the pupillary and convergence reflexes.

The Ear: Hearing and Balance

• Identify the structures of the external, middle, and internal ear, and list the functions of each.
• Explain the function of the organ of Corti in hearing.
• Define sensorineural and conductive deafness and list possible causes of each.
• Explain how one is able to localize the source of a sound.
• Describe how the equilibrium organs help maintain balance.

Chemical Senses: Taste and Smell

• Describe the location, structure, and function of the olfactory and taste receptors.
• Name the four basic taste sensations and list factors that modify the sense of taste.

Developmental Aspects of the Special Senses

• Describe changes that occur with age in the special sense organs.

Nervous System

You are driving down the freeway, and a horn blares on your right. You swerve to your left. Charlie leaves a note on the kitchen table: "See you later-have the stuff ready at 6." You know that the "stuff" is chili with taco chips. You are dozing, and your infant son makes a soft cry. Instantly, you awaken. What do all these events have in common? They are all everyday examples of the functioning of your nervous system, which has your body cells humming with activity nearly all the time.

The nervous system is the master controlling and communicating system of the body. Every thought, action, and emotion reflects its activity. Its signaling device, or means of communicating with body cells, is electrical impulses, which are rapid and specific and cause almost immediate responses.
Objective Checklist

Organization of the Nervous System

• List the general functions of the nervous system.
• Explain the structural and functional classifications of the nervous system.
• Define central nervous system and peripheral nervous system and list the major parts of each.

Nervous Tissue: Structure and Function

• State the function of neurons and neuroglia.
• Describe the general structure of a neuron and name its important anatomical regions.
• Describe the composition of gray matter and white matter.
• List the two major functional properties of neurons.
• Classify neurons according to structure and function.
• List the types of general sensory receptors and describe their functions.
• Describe the events that lead to the generation of a nerve impulse and its conduction from one neuron to another.
• Define reflex arc and list its elements.

Central Nervous System

• Identify and indicate the functions of the major regions of the cerebral hemispheres, diencephalon, brain stem, and cerebellum on a human brain model or diagram.
• Name the three meningeal layers and state their functions.
• Discuss the formation and function of cerebrospinal fluid and the blood-brain barrier.
• Compare the signs of a CVA with those of Alzheimer's disease; of a contusion with those of a concussion.
• Define EEG and explain how it evaluates neural functioning.
• List two important functions of the spinal cord.
• Describe spinal cord structure.

Peripheral Nervous System

• Describe the general structure of a nerve.
• Identify the cranial nerves by number and by name, and list the major functions of each.
• Describe the origin and fiber composition of (a) ventral and dorsal roots, (b) the spinal nerve proper, and (c) ventral and dorsal rami.
• Discuss the distribution of the dorsal and ventral rami of spinal nerves.
• Name the four major nerve plexuses, give the major nerves of each, and describe their distribution.
• Identify the site of origin and explain the function of the sympathetic and parasympathetic divisions of the autonomic nervous system.
• Contrast the effect of the parasympathetic and sympathetic divisions on the following organs: heart, lungs, digestive system, blood vessels.

Developmental Aspects of the Nervous System

• List several factors that may have harmful effects on brain development.
• Briefly describe the cause, signs, and consequences of the following congenital disorders: spina bifida, anencephaly, cerebral palsy.
• Explain the decline in brain size and weight that occurs with age.
• Define senility and list some possible causes.

Muscular System

Because flexing muscles look like mice scurrying beneath the skin, some scientist long ago dubbed them muscles, from the Latin word mus meaning "little mouse." Indeed, the rippling muscles of professional boxers or weight lifters is often the first thing that comes to mind when one hears the word muscle. But muscle is also the dominant tissue in the heart and in the walls of other hollow organs of the body. In all its forms, it makes up nearly half the body's mass.

The essential function of muscle is contraction, or shortening-a unique characteristic that sets it apart from any other body tissue. As a result of this ability, muscles are responsible for essentially all body movement and can be viewed as the "machines" of the body.

Objective Checklist

Overview of Muscle Tissues

• Describe similarities and differences in the structure and function of the three types of muscle tissue and indicate where they are found in the body.
• Define muscular system.
• Define and explain the role of the following: endomysium, perimysium, epimysium, tendon, and aponeurosis.

Microscopic Anatomy of Skeletal Muscle

• Describe the microscopic structure of skeletal muscle and explain the role of actin- and myosin-containing myofilaments.

Skeletal Muscle Activity

• Describe how an action potential is initiated in a muscle cell.
• Describe the events of muscle cell contraction.
• Define graded response, tetanus, isotonic and isometric contractions, and muscle tone as these terms apply to a skeletal muscle.
• Describe three ways in which ATP is regenerated during muscle activity.
• Define oxygen debt and muscle fatigue and list possible causes of muscle fatigue.
• Describe the effects of aerobic and resistance exercise on skeletal muscles and other body organs.

Muscle Movements, Types, and Names

• Define origin, insertion, prime mover, antagonist, synergist, and fixator as they relate to muscles.
• Demonstrate or identify the different types of body movements.
• List some criteria used in naming muscles.

Gross Anatomy of Skeletal Muscles

• Name and locate the major muscles of the human body (on a torso model, muscle chart, or diagram) and state the action of each.

Developmental Aspects of the Muscular System

• Explain the importance of a nerve supply and exercise in keeping muscles healthy.
• Describe the changes that occur in aging muscles.

Skeletal SystemThe skeleton is subdivided into two divisions: the axial skeleton, the bones that form the longitudinal axis of the body, and the appendicular skeleton, the bones of the limbs and girdles. In addition to bones, the skeletal system includes joints, cartilages, and ligaments (fibrous cords that bind the bones together at joints). The joints give the body flexibility and allow movement to occur.
Objective Checklist

Bones: An Overview

• Identify the subdivisions of the skeleton as axial or appendicular.
• List at least three functions of the skeletal system.
• Name the four main kinds of bones.
• Identify the major anatomical areas of a long bone.
• Explain the role of bone salts and the organic matrix in making bone both hard and flexible.
• Describe briefly the process of bone formation in the fetus and summarize the events of bone remodeling throughout life.
• Name and describe the various types of fractures.

Axial Skeleton

• On a skull or diagram, identify and name the bones of the skull.
• Describe how the skull of a newborn infant (or fetus) differs from that of an adult, and explain the function of fontanels.
• Name the parts of a typical vertebra and explain in general how the cervical, thoracic, and lumbar vertebrae differ from one another.
• Discuss the importance of the intervertebral discs and spinal curvatures.
• Explain how the abnormal spinal curvatures (scoliosis, lordosis, and kyphosis) differ from one another.

Appendicular Skeleton

• Identify on a skeleton or diagram the bones of the shoulder and pelvic girdles and their attached limbs.
• Describe important differences between a male and female pelvis.

Joints

• Name the three major categories of joints and compare the amount of movement allowed by each.

Developmental Aspects of the Skeleton

• Identify some of the causes of bone and joint problems throughout life.