Lecture Notes: Chapter 1-8 - Anatomy & Physiology Vocabulary Flashcards
Quick course reminders
Fixed the link on the chemistry video; access should be available for everyone. If not, watch it.
All the listed tasks are due by the 15th.
Important date: Wednesday, October 8 is your first midterm exam.
The instructor emphasizes that some topics (like the sneeze-eye closure question) are more for engagement and testability; ensure you know the core anatomy and physiology concepts below.
Sneeze reflex and whole-body reflexes
Question origin: a student asks if you can sneeze with eyes open; the teacher explains this is a body-wide reflex.
Involves multiple muscles: eyes, larynx, thorax, diaphragm, abdomen, and sphincters.
Urinary stress incontinence can occur during sneezing due to reflex activation of sphincters.
For most people (about 99%), sneezing requires eyes to close; a small minority may not, but that is not common test material.
Takeaway: sneezing is a body-wide reflex with involuntary, brainstem-mediated muscle contractions.
Abdominal quadrants vs. nine regions
Initial four-quadrant scheme (right/left upper quadrant, right/left lower quadrant) is basic but insufficient for detailed anatomy.
Abdominal-pelvic cavity is divided into nine regions (tic-tac-toe board):
Umbilical region (center); named for the belly button.
Right hypochondriac; epigastric; left hypochondriac (top row).
Right lumbar; umbilical (center); left lumbar (middle row).
Right iliac (inguinal); hypogastric; left iliac (iliac region) (bottom row).
Side references are made with the patient in mind (right/left are from the patient’s perspective, not the observer’s).
Example placements from the talk:
Gallbladder is typically in the right upper quadrant; the green color is a textbook convention, but real gallbladders can look greenish-yellow.
Appendix commonly located in the right inguinal region but can extend into the hypogastric region.
Cecum is firmly in the right iliac region.
Spleen is located high under the left floating ribs; its lower edge aligns with the left hypochondriac region.
Upper spleen relates to the left hypochondriac region; other structures may span adjacent regions.
Key anatomical quadrants and concepts:
Costal cartilage is the connection point for ribs to the sternum.
Hypochondriac regions relate to below the cartilage; epigastric is above the stomach; hypogastric is below the stomach.
The term hypochondriac etymology: hypo = below; chondro = cartilage; con refers to cartilage-related structures around ribs (costal cartilage).
Epigastric region is above the stomach; hypogastric is below the stomach.
Epigastric and hypochondriac regions are adjacent to the costal cartilage and ribs.
The talk emphasizes using the tic-tac-toe board as a mental map to locate organs and describe their regional anatomy.
Cavities and linings
Cavities in the body include:
Orbital cavities (eyes)
Nasal cavity
Middle ear cavities
Oral and digestive cavities
These are body cavities that are exposed to the exterior in some sense (open to the outside or connected to the outside through tubes).
Synovial cavities are inside joints; they secrete synovial fluid, enabling frictionless movement in freely movable joints.
Lungs are covered by visceral pleura; the pleural cavity is the space between visceral and parietal pleura.
The liver is primarily in the abdominal cavity (intraperitoneal in many places); peritoneal cavity involvement is common in anatomy discussions.
Joints, movements, and motions
General idea: joints allow different types of movement; many terms describe the ways bones move relative to each other.
Gliding (planar) joints:
Definition: movement where there is no significant change in the angle of the joint; bones slide past one another.
Examples: carpals of the wrist, tarsals of the foot; acromioclavicular joint; sternoclavicular joint.
Flexion and extension:
Flexion: decrease in the angle between bones at a joint.
Extension: increase in the angle between bones at a joint.
Examples: elbow flexion/extension; wrist flexion/extension; neck flexion/extension; knee flexion/extension; hip flexion/extension.
Trunk actions: sit-up is trunk flexion.
Hyperextension:
Definition: extension beyond the anatomical position (beyond 180 degrees in some joints).
Lateral flexion:
Movement to the side; e.g., lateral flexion of the neck or trunk (teacup analogy).
Dorsiflexion and plantarflexion:
Plantarflexion: pointing the toes downward; e.g., standing on tiptoes.
Dorsiflexion: lifting the foot so that the dorsum (top) moves toward the shin.
Abduction, adduction, and circumduction:
Abduction: moving a limb away from the midline.
Adduction: moving toward the midline.
Circumduction: circular movement combining flexion, extension, abduction, and adduction.
Shoulder movements and rotation:
Shoulder flexion/extension: raising the arm forward/upward vs back.
Medial (internal) and lateral (external) rotation: rotating the humerus toward or away from the midline.
Rotator cuff injuries can impair lateral rotation due to overdevelopment of medial rotators.
Elevation and depression:
Elevation: lifting a part (e.g., shoulders).
Depression: lowering a part.
Protraction and retraction:
Protraction: moving a part forward (e.g., mandible forward; anterior scapular movement).
Retraction: moving backward (retracting scapula).
Inversion and eversion:
Specific to the feet; inversion is turning the sole inward; eversion turns the sole outward.
Supination, pronation, and opposition:
Supination: rotation turning the palm/anterior surface upward.
Pronation: rotation turning the palm downward.
Opposition: bringing the thumb and fingertips together—distinctive of humans.
Practical notes:
Medial rotation is common to many movements; excessive development of medial rotators (e.g., latissimus dorsi, pectoralis major) can pull the shoulder forward and hamper lateral rotation.
The instructor emphasizes learning the origin, insertion, and action for each muscle in labs.
Quick reflections:
Shoulder movements are particularly tricky to memorize due to several planes and joint interactions.
The anatomy of the joints must be connected to their movements to predict what actions are possible or limited.
Homeostasis, regulation, and feedback concepts
Homeostasis overview:
Macroscopically static: the large-scale internal environment remains roughly constant (e.g., core temperature around 37°C).
Microscopically dynamic: cellular- or molecular-level adjustments continuously occur to maintain the overall constant state.
Key components of a homeostatic reflex:
Stimulus: triggers a change in a variable.
Receptor: detects the change.
Afferent pathway (input): carries information toward the control center.
Control center: processes the signal and determines an appropriate response.
Efferent pathway (output): carries the command from the control center to the effector.
Effector: responds to restore the variable toward homeostasis.
Response: the result that reduces or eliminates the stimulus.
Intrinsic (autoregulatory) vs. extrinsic regulation:
Intrinsic/autoregulation: cells/tactors within an organ or tissue adjust itself automatically to a stimulus.
Extrinsic regulation: the brain or endocrine system modulates or overrides local responses to restore homeostasis.
Intracellular vs. intercellular regulation:
Intracellular: processes inside cells (e.g., delta cells in the pancreas releasing somatostatin to modulate insulin release).
Intercellular: signals between different cells (e.g., hormones or neural signals coordinating responses).
Baroreceptors and autonomic regulation:
Baroreceptors detect blood pressure in large arteries (e.g., carotid sinuses).
They respond by signaling vasodilation or vasoconstriction to adjust blood pressure.
Negative feedback loops (the most common in physiology):
A stimulus changes a variable, the system detects it, and the response reduces the deviation from the set point.
Classic thermostat analogy: room temperature dropping triggers the thermostat to signal heating; the building warms back toward the set point.
Examples include temperature regulation and blood glucose homeostasis.
Negative feedback in the body with a focusing example:
Temperature regulation: skin thermoreceptors send input to the hypothalamus (thermoregulatory center).
If too hot, hypothalamus vasodilates vessels in limbs to increase heat loss and initiates sweating; evaporation cools the body.
Blood glucose regulation: insulin and glucagon maintain a normal level around roughly G ext{ at } ext{about } 90 ext{ mg/dL}.
A decrease in blood glucose triggers alpha cells to release glucagon; insulin release moderates glucose uptake.
The set point range and individual variation mean that exact values can vary between individuals and contexts.
Set point and range concepts:
Set point is the target value; the body often maintains a range rather than a single exact value.
Sleep and activity can shift set points temporarily; homeostasis aims to stay within a functional range rather than an exact number.
Normal historical body temperature trends:
Average body temperature in North America has shown a gradual decline over the last century, potentially due to improvements in reducing systemic inflammation.
Positive feedback loops (less common for maintaining homeostasis):
These amplify the original stimulus and push the system away from the set point temporarily, often to a decisive endpoint.
Classic example: labor and childbirth—oxytocin release intensifies uterine contractions, pushing toward delivery.
Detrimental example discussed: congestive heart failure (CHF) where hypertension increases cardiac workload; the left ventricle enlarges, reducing efficiency and causing a vicious cycle that worsens heart function.
Hormonal regulation examples (intrinsic vs extrinsic):
Intrinsic example: pancreatic delta cells secrete somatostatin, which inhibits insulin release, contributing to intrinsic regulation of blood glucose.
Extrinsic example: baroreceptor signals influence autonomic output to maintain blood pressure, illustrating extrinsic regulation by the nervous system.
Clinical connections and testable implications:
Negative feedback loops are a foundational concept and are commonly tested.
Understanding intrinsic vs extrinsic and intracell vs intercellular regulation helps in diagnosing dysregulation scenarios (e.g., endocrine disorders, autonomic dysfunction).
Positive feedback processes often signal a transition to a new physiological state or a pathophysiological condition (e.g., CHF).
Quick illustrative equations (LaTeX):
Negative feedback dynamic (generic form):
\frac{dX}{dt} = -k\,(X - X_0)
Glucose regulation simplified: G \rightarrow[\text{stimulus}] \text{(glucagon/insulin)} \rightarrow [\text{response}] G\approx G_0
Mental model tips for exams:
Remember the flow: Stimulus → Receptor → Afferent signal → Control center → Efferent signal → Effector → Response.
Distinguish intrinsic/autoregulation from extrinsic regulation and intracellular/intercellular regulation.
Use the nine-region map to place organs and relate clinical scenarios (e.g., appendix location, spleen beneath left ribs).
Link movement terms to real-world actions (e.g., sit-ups involve trunk flexion; plantarflexion is toe-pointing; circumduction is a multi-planar shoulder/hip motion).
Quick reference: common terms and concepts (glossary)
Umbilical region: central region around the belly button.
Hypochondriac regions: regions below the costal cartilage; left and right sides.
Epigastric region: region over the stomach; above the stomach.
Hypogastric region: region below the stomach.
Iliac region: upper parts of the hip bones; often associated with the iliac crest.
Anterior superior iliac spine: a palpable pelvic landmark on the ilium; relates to the hip/iliac region.
Synovial cavity: a joint cavity filled with synovial fluid for lubrication and mobility.
Visceral pleura: the membrane directly covering the lungs.
Visceral cavity: internal surfaces and organs; peritoneal cavity lines many abdominal organs.
Somatostatin, insulin, glucagon: key regulators of glucose homeostasis; delta cells inhibit insulin to modulate glucose levels.
Baroreceptors: pressure sensors in arteries that help regulate blood pressure via autonomic pathways.
Sneeze reflex: widespread reflex involving many body systems; can influence pelvic floor and sphincter function.
Positive feedback examples: childbirth (labor), pathogenic amplification in disease states (e.g., CHF progression).
Negative feedback examples: body temperature regulation, blood glucose maintenance, hormonal regulation via insulin/glucagon.
Connections to broader course relevance
Homeostatic principles underpin physiology and clinical reasoning across systems (endocrine, nervous, musculoskeletal).
Understanding regions and cavities supports diagnostic reasoning and interpretation of imaging and surgical planning.
Knowledge of joint movements aids in studying biomechanics and physical examination.
Recognizing intrinsic vs extrinsic and intracellular vs intercellular regulation helps in understanding disease mechanisms and therapeutic targets.