Ross and Wilson Anatomy: The Human Body

• Ross and Wilson is a core anatomy and physiology text for over 50 years
• Provides a straightforward description of body systems and their functions
• Describes common age-related changes and considers relevant disorders and diseases

The Human Body

• Presented system by system.
• Physiology is an integrated subject and systems function cooperatively to maintain health
• The first three chapters provide an overview of the body and describe its main structures.
• Later chapters are structured into sections: communication, intake/elimination, and protection/survival.
• There is a companion website with animations and self-test activities: https://evolve.elsevier.com/Waugh/anatomy/

Structural Complexity

• Atoms combine to form molecules.
• Cells are the smallest independent units of living matter
• Different cell types have specialized functions.
• Tissues are cells with similar structures and functions.
• Organs are made of different tissues for specific functions.
• Systems consist of organs and tissues contributing to survival needs
• The human body is dependent on systems carrying out specific functions

Internal Environment and Homeostasis

• The external environment surrounds the body and provides oxygen/nutrients.
• The skin is a barrier between tissues and the external environment
• The internal environment is the water-based medium in which body cells exist.
• Interstitial or tissue fluid bathes cells which absorb oxygen/nutrients from this fluid
• Cellular wastes diffuse into the bloodstream via the interstitial fluid.
• Homeostasis maintains a tightly controlled composition of the internal environment.
• Control systems consist of a detector, control center, and effector
• Negative feedback negates movements away from the normal set points
• Positive feedback progressively increases the response
• Homeostatic imbalance happens when control of a variable factor fails and may threaten health or life

Survival Needs

• Body systems are described separately, but work interdependently.
• Transport systems include blood, lymphatic, and cardiovascular systems
• Internal communication includes the nervous and endocrine systems
• External communication includes special senses, verbal and non-verbal
• Intake and elimination: includes intake of oxygen and nutrients, and elimination of wastes (carbon dioxide, urine, faeces)
• Protection and survival: includes protection against external env't(skin), defence against infection, movement and survival of species

Transport systems - The Blood

• Transports substances around the body through vessels
• Volume: adults have 5-6 litres of blood
• Components: plasma (fluid), and blood cells suspended in the plasma
• Plasma is mainly water, containing nutrients, oxygen, chemical substances, and waste materials.
• Blood cells are classified by function.

Cardiovascular System

• Consists of a network of blood vessels and the heart. Three types: arteries, veins and capillaries
• Capillaries are vessels with thin walls which enables exchange of substances between blood and body
• Blood vessels transport blood to lungs (pulmonary circulation) and cells in all other parts of the body (systemic circulation)
• The heart is a muscular sac with four chambers
• The heart pumps blood round the body
• The heart beats 65-75 times per minute at rest (increased rate during activity)
• Taking the pulse counts the rate at which the heart beats

Lymphatic System

• Consists of lymph vessels, which begin as blind-ended tubes in interstitial spaces
• Lymph is tissue fluid containing plasma proteins/cell debris
• Lymph is transported along vessels + connects to the bloodstream near the heart
• Lymph nodes filter lymph, removing microbes, etc
• The lymphatic system is the site for formation/maturation of lymphocytes

Internal Communication: the Nervous System

• The nervous system facilitates communication
• Components of the central nervous system: brain, located inside the skull, spinal cord that extends from the base of the skull to the lumbar region
• The peripheral nervous system is a network of sensory/afferent nerves and motor/efferent nerves
• Somatic senses: pain, touch, heat & cold which arise from specialized sensory receptors in the skin Receptors in muscles/ joints respond to changes in position and maintain posture
• Some receptors are activated by stimuli in internal organs/ control body functions
• Nerve impulses (action potentials) travel at great speed for rapid adjustments
• nerves communicate w/ each such other by releasing a neurotransmitter
• Sensory nerves pass impulses to part of the brain, where the info is analyzed/ collated
• Many aspects of body function are monitored and adjusted, usually by negative feedback control and usually subconsciously
• reflex actions are fast, involuntary and protective responses to stimuli