TEAS Science Anatomy and Physiology Review: Foundational Concepts
Anatomical Terminology and Body Planes
Navigating anatomy for TEAS test questions requires a precise vocabulary of directional terms and spatial relationships. The exam frequently employs terms like proximal and distal to describe positions on the limbs relative to the trunk, or superior and inferior for vertical relationships. A common point of confusion for candidates is the distinction between ipsilateral (same side) and contralateral (opposite side), which often appears in neurological or musculoskeletal scenarios. You must also master the three primary anatomical planes: the sagittal plane, which divides the body into left and right sections; the frontal (coronal) plane, which separates anterior from posterior; and the transverse (axial) plane, which creates superior and inferior halves. Understanding these planes is vital for interpreting cross-sectional diagrams of the brain or torso. Furthermore, knowing the difference between the ventral and dorsal cavities—and the specific organs housed within the thoracic, abdominal, and pelvic regions—is a prerequisite for identifying where specific physiological processes occur.
Levels of Organization: Cells to Organ Systems
Biological hierarchy is a recurring theme in TEAS 7 science content. The exam tests your ability to trace a physiological function from the chemical level up to the organismal level. At the cellular level, you must understand how specialized structures like mitochondria or ribosomes support the unique needs of different tissues. For example, muscle cells contain a high density of mitochondria to support ATP-intensive contractions, while goblet cells in the respiratory tract are rich in Golgi apparatuses for mucus secretion. Moving to the tissue level, you will encounter the four primary types: epithelial, connective, muscle, and nervous. The TEAS often asks about the specific locations of stratified squamous epithelium (protection) versus simple columnar epithelium (absorption). Recognizing that an organ like the stomach contains all four tissue types working toward a single function—digestion—demonstrates the integrative thinking required to score in the advanced bracket on the science subsection.
The Principle of Homeostasis and Feedback Loops
Homeostasis is the cornerstone of human physiology, representing the dynamic equilibrium maintained by the body. Physiology TEAS questions often focus on the mechanisms of negative feedback, where the body’s response reverses a stimulus to return to a set point. A classic exam example is thermoregulation: when the hypothalamus detects an increase in core temperature, it triggers vasodilation and sweating to dissipate heat. Conversely, positive feedback loops, though rarer, are equally testable. These involve a response that reinforces the stimulus until a culminating event occurs, such as the release of oxytocin during childbirth to increase uterine contractions. You should be prepared to identify the components of these loops: the sensor (receptor), the control center (integrator), and the effector (organ or gland). Scoring well depends on your ability to predict what happens when these loops fail, leading to pathological states like diabetes or hypertension.
The Support and Movement Systems: Skeletal and Muscular
Major Bones, Joints, and Skeletal Functions
The skeletal system provides more than just a structural framework; it is an active metabolic organ system. In a TEAS A&P study guide, you must distinguish between the axial skeleton (skull, vertebral column, rib cage) and the appendicular skeleton (limbs and girdles). The exam frequently tests the microscopic anatomy of bone, specifically the osteon or Haversian system. You must know the roles of osteoblasts (bone-forming cells), osteoclasts (bone-resorbing cells), and osteocytes (mature bone cells). Furthermore, the skeletal system's role in hematopoiesis—the production of blood cells within the red bone marrow—is a high-yield concept. Joint classification is another area of focus, ranging from immovable synarthroses (like cranial sutures) to highly mobile diatheses (synovial joints). Understanding the function of ligaments (connecting bone to bone) versus tendons (connecting muscle to bone) is essential for answering questions about musculoskeletal stability and movement mechanics.
Types of Muscle Tissue and Contraction
Muscular physiology on the TEAS centers on the three types of muscle tissue: skeletal, cardiac, and smooth. Skeletal muscle is striated and voluntary, characterized by multinucleated fibers. Cardiac muscle is also striated but involuntary, featuring intercalated discs that allow for rapid electrical signaling between cells. Smooth muscle is non-striated and involuntary, found in the walls of hollow organs like the intestines and blood vessels. The mechanism of contraction is governed by the Sliding Filament Theory. This process begins when an action potential reaches the neuromuscular junction, triggering the release of acetylcholine. This leads to the release of calcium ions from the sarcoplasmic reticulum, which bind to troponin. This binding shifts tropomyosin, exposing active sites on actin filaments for myosin heads to bind, forming cross-bridges. This molecular sequence is a frequent target for multi-step sequencing questions on the exam.
How Bones and Muscles Work Together
The interaction between the skeletal and muscular systems is best understood through the lens of biomechanics. Muscles act as the "engine" while bones serve as "levers." In TEAS human body systems questions, you may be asked to identify the origin (the stationary attachment point) and the insertion (the attachment point on the bone that moves). Movement is usually the result of antagonistic pairs: the agonist (prime mover) contracts while the antagonist relaxes. For example, during elbow flexion, the biceps brachii is the agonist and the triceps brachii is the antagonist. Synergists are muscles that assist the prime mover or stabilize the joint. This section of the exam also touches on the nervous system's role in motor unit recruitment, where a single motor neuron and all the muscle fibers it innervates work as a functional unit. Understanding the relationship between muscle tone and skeletal posture is vital for clinical scenarios involving patient mobility and injury.
Regulation and Control: Nervous and Endocrine Systems
Central vs. Peripheral Nervous System Structure
The nervous system is divided into the Central Nervous System (CNS), comprising the brain and spinal cord, and the Peripheral Nervous System (PNS), which includes all cranial and spinal nerves. The TEAS focuses heavily on the functional divisions of the PNS: the Somatic Nervous System (voluntary control of skeletal muscles) and the Autonomic Nervous System (ANS) (involuntary control of smooth muscle, cardiac muscle, and glands). The ANS is further split into the sympathetic nervous system, which initiates the "fight or flight" response, and the parasympathetic nervous system, which governs "rest and digest" activities. You must know that the sympathetic response increases heart rate and dilates pupils, while the parasympathetic response stimulates digestion and slows the heart. Questions may also cover the major regions of the brain, such as the cerebellum (coordination and balance), the medulla oblongata (autonomic functions like breathing), and the cerebrum (higher-level cognition).
Neuron Function and Synaptic Transmission
The functional unit of the nervous system is the neuron. A typical neuron consists of a cell body (soma), dendrites that receive signals, and an axon that transmits impulses. Many axons are insulated by a myelin sheath, produced by Schwann cells in the PNS or oligodendrocytes in the CNS, which increases the speed of signal conduction via saltatory conduction. The transmission of a signal between neurons occurs at the synapse. When an action potential reaches the axon terminal, voltage-gated calcium channels open, causing neurotransmitters to be released into the synaptic cleft via exocytosis. These chemicals bind to receptors on the postsynaptic membrane, potentially triggering a new action potential. The TEAS may ask about specific neurotransmitters, such as glutamate (the primary excitatory transmitter) or GABA (the primary inhibitory transmitter), and how their balance affects neurological health.
Key Glands, Hormones, and Their Target Organs
The endocrine system regulates long-term physiological processes through the secretion of hormones directly into the bloodstream. The hypothalamus serves as the master link between the nervous and endocrine systems, controlling the pituitary gland. You must memorize the "axis" relationships, such as the hypothalamic-pituitary-adrenal (HPA) axis. Key hormones to master include insulin and glucagon from the pancreas (regulating blood glucose), thyroxine from the thyroid (regulating metabolism), and epinephrine from the adrenal medulla (stress response). The TEAS also emphasizes the difference between lipid-soluble hormones (like steroids), which can cross the cell membrane to bind to intracellular receptors, and water-soluble hormones (like peptides), which bind to surface receptors and utilize second messenger systems like cAMP. Understanding these mechanisms is crucial for answering questions about hormonal imbalances and their systemic effects.
Transport and Exchange: Cardiovascular and Respiratory Systems
Path of Blood Through the Heart and Circulatory Pathways
Blood flow through the heart is a fundamental topic in any TEAS science anatomy and physiology review. Deoxygenated blood enters the right atrium via the superior and inferior vena cava, passes through the tricuspid valve into the right ventricle, and is pumped through the pulmonary valve to the lungs. Oxygenated blood returns to the left atrium via pulmonary veins, moves through the mitral (bicuspid) valve to the left ventricle, and is ejected through the aortic valve into the systemic circulation. The left ventricle has the thickest muscular wall because it must generate enough pressure to perfuse the entire body. Furthermore, you must understand the cardiac cycle, specifically systole (contraction/ejection) and diastole (relaxation/filling). The electrical conduction system, starting at the Sinoatrial (SA) node (the natural pacemaker), ensures the heart beats in a coordinated fashion, a process often depicted on EKG strips that may appear in exam questions.
Structures of the Respiratory Tract and Gas Exchange
The respiratory system’s primary function is the exchange of oxygen and carbon dioxide. Air travels through the nasal cavity, pharynx, larynx, trachea, and into the bronchi, which branch into smaller bronchioles. The terminal ends of this pathway are the alveoli, tiny grape-like sacs where gas exchange occurs. These alveoli are coated in surfactant, a fluid that reduces surface tension and prevents lung collapse. Gas exchange happens via passive diffusion across the alveolar-capillary membrane, driven by partial pressure gradients. Oxygen binds to hemoglobin in red blood cells for transport, while carbon dioxide is mostly transported as bicarbonate ions in the plasma. The TEAS often tests the mechanics of breathing: during inhalation, the diaphragm and external intercostal muscles contract, increasing thoracic volume and decreasing internal pressure (Boyle’s Law), which draws air into the lungs.
Interdependence of Circulation and Respiration
The cardiovascular and respiratory systems are functionally inseparable. This interdependence is most evident in the regulation of blood pH. The respiratory system helps maintain an arterial pH between 7.35 and 7.45. If blood becomes too acidic (high CO2), the brain’s respiratory centers increase the rate and depth of breathing to "blow off" excess CO2, a process known as hyperventilation. Conversely, if blood is too alkaline, respiration slows. This relationship is also seen in the pulmonary circulation (the loop between the heart and lungs) versus the systemic circulation (the loop between the heart and the rest of the body). Questions on the TEAS may ask you to predict how a failure in one system, such as congestive heart failure, leads to fluid backup in the lungs (pulmonary edema), illustrating the "cause and effect" logic inherent in advanced A&P assessments.
Processing and Elimination: Digestive and Urinary Systems
The Pathway and Key Functions of the Digestive Tract
Digestion involves the mechanical and chemical breakdown of food into absorbable nutrients. The pathway begins in the mouth, where salivary amylase starts carbohydrate digestion. Food moves through the esophagus via peristalsis—rhythmic muscle contractions—into the stomach. The stomach’s acidic environment (pH 1-2) activates pepsin, an enzyme that begins protein digestion. The majority of digestion and nutrient absorption occurs in the small intestine, specifically the duodenum, jejunum, and ileum. The surface area for absorption is vastly increased by villi and microvilli. Finally, the large intestine (colon) is primarily responsible for water reabsorption and the formation of feces. You should be familiar with the role of the pyloric sphincter in controlling the movement of chyme (liquefied food) into the small intestine, a common detail in gastrointestinal physiology questions.
Roles of the Liver, Pancreas, and Gallbladder
These accessory organs provide essential secretions for digestion. The liver is a metabolic powerhouse, producing bile (which emulsifies fats), detoxifying chemicals, and storing glycogen. The gallbladder stores and concentrates bile, releasing it into the duodenum in response to fatty meals. The pancreas has both endocrine and exocrine functions; its exocrine role involves secreting pancreatic juice containing bicarbonate (to neutralize stomach acid) and a suite of enzymes like lipase, amylase, and proteases (trypsinogen). Understanding the hormonal triggers for these secretions, such as cholecystokinin (CCK) and secretin, is vital for advanced TEAS preparation. Questions may ask you to identify which organ is malfunctioning based on a patient's inability to digest a specific macronutrient, such as lipids.
Kidney Structure, Nephron Function, and Waste Removal
The urinary system maintains homeostasis by filtering blood and regulating electrolytes. The functional unit of the kidney is the nephron. Blood enters the glomerulus, where high pressure forces fluid and solutes into Bowman’s capsule (filtration). As this filtrate moves through the proximal tubule, loop of Henle, and distal tubule, the body reabsorbs essential substances like glucose and water while secreting wastes like urea and creatinine. The Loop of Henle is particularly important for concentrating urine through a countercurrent multiplier system. Hormonal regulation plays a huge role here: Antidiuretic Hormone (ADH) increases water reabsorption in the collecting ducts, while Aldosterone increases sodium reabsorption. Mastery of the renin-angiotensin-aldosterone system (RAAS) is often the difference between an average and a high score on the TEAS 7 science content.
Integration and Application of A&P Knowledge
Analyzing Interactions Between Multiple Body Systems
The TEAS exam rarely tests a system in isolation; instead, it looks for your ability to see the "big picture." For example, a question might ask how the integumentary and cardiovascular systems work together to lower body temperature (vasodilation of surface capillaries and sweat production). Another common scenario involves the skeletal and endocrine systems, where parathyroid hormone stimulates osteoclasts to break down bone matrix to increase blood calcium levels. You must also understand how the renal system interacts with the cardiovascular system to regulate blood pressure via fluid volume control. Recognizing these "cross-talk" mechanisms is essential, as they reflect the clinical reality of nursing where a symptom in one system often originates from a pathology in another.
Applying A&P to Clinical and Scenario-Based Questions
Scenario-based questions require you to apply physiological rules to a hypothetical patient. You might be presented with a patient who has a high respiratory rate and asked to determine the likely effect on their blood pH (respiratory alkalosis). Or, you may be asked to predict the effect of a medication that blocks calcium channels on cardiac muscle contraction (decreased force of contraction). These questions test your ability to use cause-effect reasoning. To prepare, practice mapping out the consequences of an organ failure. If the liver fails, what happens to bile production? How does that affect fat-soluble vitamin absorption? This level of inquiry prepares you for the "select all that apply" or "ordered response" question types that are increasingly common in the TEAS 7 format.
Identifying High-Yield Diagrams and Lab Values
Visual literacy is a major component of the TEAS Science section. You should be able to identify structures on diagrams of the heart, the brain, the nephron, and the skin. Labeling the layers of the integumentary system—epidermis, dermis, and hypodermis—and knowing which contains blood vessels and nerves is a frequent requirement. Additionally, you should have a baseline understanding of normal lab values and physiological metrics, such as a standard resting heart rate (60-100 bpm), normal blood pressure (120/80 mmHg), and typical blood pH (7.35-7.45). While the TEAS is not a clinical nursing exam, it uses these values to set the stage for physiology questions. Being comfortable with these numbers allows you to quickly identify "abnormal" states in a question stem, leading you more efficiently to the correct physiological explanation.