Topic 1.1 Foundations of Animal Anatomy and Physiology

An understanding of normal anatomy and physiology provides the foundation for recognising health, disease and injury in assistance animals. Before Occupational Therapists can identify signs of compromised welfare, respond appropriately to health concerns or collaborate effectively with veterinary professionals, they must first understand how the healthy animal body is structured and functions. Although Occupational Therapists are not responsible for diagnosing or treating veterinary conditions, a sound understanding of normal biological processes enables practitioners to recognise when an animal may require further assessment and supports timely referral to veterinary care.

Anatomy is the study of body structure, including bones, muscles, organs, tissues and body systems. Physiology is the study of how these structures function and interact to maintain life. Together, anatomy and physiology provide the scientific basis for understanding movement, behaviour, growth, healing and adaptation. Because body systems function interdependently, changes affecting one system frequently influence the health and performance of others. For example, musculoskeletal pain may reduce mobility and participation in occupational tasks, while respiratory disease may limit endurance, alter behaviour and affect an assistance animal’s ability to work safely.

Throughout assistance animal practice, Occupational Therapists regularly observe animals during movement, task performance and daily routines. Developing an understanding of normal posture, gait, breathing, body condition and physiological function enables practitioners to identify deviations from expected health and recognise when veterinary assessment is warranted. Early recognition of subtle changes can contribute to improved welfare outcomes, reduce the progression of disease and support continuity of occupational participation for both the handler and assistance animal.

This chapter introduces the basic principles of anatomy and physiology relevant to Occupational Therapy practice. It explores anatomical terminology, levels of biological organisation, homeostasis and the major body systems, providing the scientific foundation for understanding health, illness and injury throughout the remainder of this unit.

Why Occupational Therapists Need Knowledge of Anatomy and Physiology

Occupational Therapists working with assistance animal partnerships are not expected to diagnose veterinary conditions or provide medical treatment. However, they require sufficient knowledge of animal anatomy and physiology to recognise when physical health may be influencing behaviour, welfare or occupational performance.

Knowledge of anatomy and physiology enables Occupational Therapists to:

• recognise normal and abnormal physical presentation
• understand how illness and injury influence occupational participation
• identify early indicators of compromised health
• communicate observations accurately using appropriate anatomical terminology
• collaborate effectively with veterinary professionals
• support safe task performance and environmental participation
• contribute to timely referral when veterinary assessment is required.

This knowledge strengthens interdisciplinary practice while ensuring that practitioners remain within their professional scope.

Anatomy and Physiology: What’s the Difference?

Although anatomy and physiology are closely related, they examine different aspects of the living body.

Anatomy refers to the structure of the body.

It examines:

• bones
• joints
• muscles
• tendons and ligaments
• organs
• blood vessels
• nerves
• skin and associated structures.

Physiology refers to how these structures function.

Examples include:

• muscle contraction
• nerve conduction
• respiration
• circulation
• digestion
• hormone regulation
• immune responses
• temperature regulation.

Healthy function depends upon both normal structure and normal physiology. Disease, injury or congenital abnormalities affecting either structure or function may impair movement, behaviour, learning, welfare and occupational performance.

Levels of Biological Organisation

The body is organised into increasingly complex levels of structure.

Cells

Cells are the smallest living units of the body and perform specialised functions. Different cell types include muscle cells, nerve cells, blood cells and epithelial cells.

Tissues

Groups of similar cells combine to form tissues.

The four primary tissue types are:

• epithelial tissue
• connective tissue
• muscle tissue
• nervous tissue.

Organs

Organs consist of multiple tissue types working together to perform specialised functions.

Examples include:

• heart
• lungs
• liver
• kidneys
• brain.

Organ Systems

Organs work together as body systems to maintain life.

Examples include:

• musculoskeletal system
• nervous system
• cardiovascular system
• respiratory system
• digestive system.

The Whole Animal

All body systems function together as an integrated whole. A problem affecting one system frequently influences many others, highlighting the importance of considering the animal holistically rather than viewing body systems in isolation.

Homeostasis

Homeostasis refers to the body’s ability to maintain a relatively stable internal environment despite changes occurring both within the body and in the external environment.

Examples of physiological variables maintained through homeostasis include:

• body temperature
• blood glucose concentration
• hydration
• blood pressure
• oxygen and carbon dioxide levels
• electrolyte balance
• acid-base balance.

Numerous body systems continuously interact to maintain homeostasis through complex feedback mechanisms.

When homeostasis is disrupted by illness, injury or environmental stress, behavioural and physiological changes often occur before obvious clinical signs become apparent. Occupational Therapists should appreciate that subtle changes in behaviour, movement or task performance may represent early indicators of disrupted physiological function.

Anatomical Terminology

Consistent anatomical terminology facilitates accurate communication between Occupational Therapists, veterinarians and other members of the interdisciplinary healthcare team.

Using standard anatomical terminology supports accurate documentation and effective interdisciplinary communication.

Major Body Systems

The body consists of multiple organ systems that work together to maintain health and support occupational performance.

The major body systems include:

• integumentary system
• musculoskeletal system
• nervous system
• cardiovascular system
• respiratory system
• digestive system
• urinary system
• endocrine system
• reproductive system
• immune and lymphatic system.

Subsequent topics within this unit will examine each of these systems in greater detail and explore how disease affecting these systems influences behaviour, welfare and working ability.

Normal Variation in Assistance Animals

No two assistance animals are identical. Normal anatomy and physiology vary according to numerous biological and environmental factors.

Variation may occur due to:

• species
• breed
• age
• sex
• body size
• genetics
• reproductive status
• level of physical conditioning
• environmental conditions.

For example, brachycephalic dogs have anatomical differences affecting respiration, while senior assistance animals naturally experience changes in muscle mass, joint mobility and cardiovascular fitness. These normal variations must be considered when assessing health and determining whether veterinary referral is required.

One Health and One Welfare Perspective

Healthy assistance animals are essential partners in supporting human health, independence and occupational participation. Illness, pain or injury affecting the animal may compromise not only its own welfare but also the safety, wellbeing and functional independence of the handler.

From a One Health and One Welfare perspective, maintaining animal health benefits both members of the partnership. Occupational Therapists should therefore view physical health not as an isolated veterinary issue, but as a key determinant of participation, quality of life and sustainable assistance animal partnerships.

Clinical Snapshot

Scenario

During a routine review, an Occupational Therapist observes that a mobility assistance dog is slower to stand after resting and hesitates before retrieving dropped items. The handler believes the dog is “just slowing down with age” and has not sought veterinary advice.

Clinical reasoning

Although these changes may be associated with normal ageing, they may also indicate musculoskeletal pain, arthritis or another underlying health condition. The Occupational Therapist should objectively document observed changes in gait, posture and task performance, discuss the findings with the handler and recommend prompt veterinary assessment. Early recognition may improve treatment outcomes, support the dog’s welfare and prolong safe participation in assistance work.

The Occupational Therapist’s Role

Occupational Therapists play an important role in recognising deviations from normal health and understanding how physical health influences occupational performance.

Occupational Therapists should be able to:

• recognise normal anatomical structure and function
• identify deviations from expected health
• observe changes in movement, posture and task performance
• document objective findings using appropriate anatomical terminology
• recognise when veterinary assessment is indicated
• collaborate effectively with veterinary professionals
• integrate physical health considerations into occupational therapy clinical reasoning while remaining within professional scope.

Key Practice Principle

Understanding normal anatomy and physiology enables Occupational Therapists to recognise early indicators of illness, injury and compromised welfare, communicate effectively with veterinary professionals and support safe, evidence-based assistance animal practice. While diagnosis and treatment remain the responsibility of veterinary professionals, knowledge of normal biological function is essential for timely recognition, referral and the promotion of healthy, sustainable human–animal partnerships.