Exam 1 A&P

Anatomy: The study of structure or form, particularly in humans

- Physiology: The study of function, typically examined by organ systems

Types of Anatomical Study

Gross Anatomy - Visible without microscope or other aids

- Can be studied through different approaches:

- Regional: Studying specific body areas (e.g., head, upper limb, lower limb)

- Systemic: Studying by organ systems

- Surface anatomy is External examination

- Histology: Study of tissues using microscopes

- Cytology: Study of cells

- Histopathology: Study of abnormal tissues

- Ultra-structural level: Molecular and atomic study using electron microscopes

Physical Examination Methods

- Auscultation: Study through listening

- Observation/Inspection: Visual examination

- Palpation: Examination through touch

- Percussion: Combined listening and touching technique

- Dissection: Physical separation of tissues

Modern Methods

- Medical imaging (e.g., MRI)

- Exploratory surgery (e.g., for conditions like endometriosis)

Comparative Studies

- Comparative Anatomy: Study of anatomical structures across different species

- Comparative Physiology: Study of functional differences across species

- Important for drug development and medical treatments

- Vestigial organs are structures that no longer serve their original functional purpose

- Examples in humans include:

- Male nipples - non-functional

- Coccyx - can cause complications during childbirth

- Wisdom teeth - originally needed due to tooth loss, now often removed

- Erector pili muscles - cause goosebumps but serve little purpose

- Appendix - can be removed without impact

- Tonsils - part of immune system but not essential

- Vomeronasal organ - non-functional sensory organ in nasal cavity

- Auricularis muscle - allows ear wiggling in few people

- Fifth toe - not essential for balance

- Plica semilunaris - remnant eye membrane, functional in sharks

Human Classification

- Kingdom: Animalia

- Phylum: Chordata (having vertebrae)

- Class: Mammalia

- Order: Primates (includes humans, apes, monkeys)

Primate Adaptations

- Arboreal capabilities with highly mobile shoulder joint

- Opposable thumb (critical for grip and manipulation)

- Forward-facing eyes providing depth perception

- Color vision for food selection

- Fewer skull bones for increased strength

- Bipedalism advantages:

- Frees upper limbs

- Increased brain size

- Bipedalism challenges:

- More difficult childbirth

- Delayed neural development

- Full neural development age:

- Females: 18-23 years

- Males: 21-27 years

Atoms - smallest unique units

Molecules - combinations of atoms

Organelles - cellular structures (nucleus, mitochondria)

Cells - smallest viable unit of life

Tissues - groups of similar cells

Organs - formed by multiple tissue types

Organ systems - multiple organs working together

Organism - complete living being

Medical Approaches

- Reductionism: Focus on specific parts/systems

- Specialized medical care

- Risk of missing broader issues

- Holism: Treating the whole person

- Integration of DO and MD approaches

- Considers overall patient condition

Health and Energy

- ATP is the primary energy molecule

- Disease/injury requires increased energy expenditure

- Avoid exercise when sick due to hypermetabolic state

- Physical appearance can indicate health status

- Organization disruption leads to pathophysiology (abnormal function)

Metabolism

- Sum of all chemical reactions occurring in an organism

- Anabolism: Building smaller parts into larger molecules (synthesis)

- Catabolism: Breaking down molecules into smaller parts

- Requires waste excretion (e.g., water vapor, perspiration,

Response to Stimuli (Afference)

- Two-part process: Detection and response

- Occurs at cellular and organism level

- Managed by two complementary systems:

- Nervous system: Fast, precise, quick to start/stop

- Endocrine system: Slower, more diffuse, longer-lasting effects

Movement (Efference)

- Internal mobility within cells (like motor proteins moving materials)

- External mobility of whole organism

- Essential for maintaining health

- Lack of mobility can compromise overall health

Homeostasis

- Maintenance of stable internal environment

- Dynamic equilibrium within normal ranges

- Examples:

- Body temperature (98.6°F)

- Hydration levels (indicated by urine color)

- Control mechanisms:

- Negative feedback: Most common, reverses changes from set point

- Positive feedback: Less common, amplifies changes (e.g., fever)

Growth and Development

Growth:

- Hypertrophy: Increase in cell size

- Hyperplasia: Increase in cell number

Development:

- Changes in form or function

- Differentiation: Cell specialization

- Stem cells: Undifferentiated cells that can become specialized

Reproduction

- Ability to produce copies of oneself

- Sexual reproduction in humans

- Cell division types:

- Mitosis: Regular cell division

- Meiosis: Production of egg and sperm cells

Evolution

- Changes in genetic makeup of populations

- Based on natural selection

- Occurs within populations, not necessarily globally

- Focused on reproductive success

## Additional Considerations

Legal Criteria for Life

Different from biological criteria:

- 24 hours without brain activity

- No reflexes

- Cannot maintain respiration

- No measurable heartbeat

### Physiological Variations

Reference standards:

- Male (22 years): 154 lbs, 2800 kcal/day

- Female (22 years): 128 lbs, 2000 kcal/day

- Historical bias: Most research based on middle-aged white males

Homeostatic Control

Blood vessel regulation:

- Vasomotion: Changes in blood vessel diameter

- Vasodilation: Increase in diameter

- Vasoconstriction: Decrease in diameter

- Helps regulate body temperature and blood distribution

Environmental Challenges

- External: Temperature, disease, oxygen levels

- Internal: Psychological stress, aging, genetic conditions

- Importance of managing multiple stressors for success (especially in academic settings)

Negative Feedback

- Maintains body stability through opposing changes

- Examples include:

Temperature Regulation

- High temperature response:

- Blood vessels dilate (vasodilation)

- Blood moves closer to skin surface

- Heat dissipates through air movement

- Low temperature response:

- Blood vessels constrict (vasoconstriction)

- Blood moves away from surface

- Preserves core temperature for vital organs

- Results in pale, cold extremities

Blood Pressure Control

- Baroreceptors in blood vessel walls detect pressure changes

- High pressure response:

- Decreased heart rate

- Vasodilation

- Low pressure response:

- Increased heart rate

- Vasoconstriction

Positive Feedback

- Amplifies changes rather than opposing them

- Normal examples:

- Childbirth

- Blood clotting

- Digestion

- Nerve signals

- Mild fever

- Can become dangerous if unchecked (high fever, excessive clotting)

Childbirth Example

1. Fetus puts pressure on cervix

2. Mechanoreceptors detect pressure

3. Brain releases oxytocin

4. Oxytocin causes uterine contractions

5. Increased pressure on cervix

6. Cycle continues until birth

# Basic Chemistry Concepts

Atoms and Elements

- Atom: Smallest unit of stable matter (not living)

- Element: Simplest form of matter made of same type of atoms

- Components:

- Protons (positive charge)

- Neutrons (neutral)

- Electrons (negative charge)

Elements in Human Body

Major Elements (98.5% of body composition)

- CHON (Carbon, Hydrogen, Oxygen, Nitrogen) - 96%

- Calcium and Phosphorus - additional 2.5%

Minor and Trace Elements

- Important elements include:

- Potassium (K)

- Sodium (Na)

- Chlorine (Cl)

- Magnesium (Mg)

- Iron (Fe)

Minerals

- Elements absorbed from soil through plants

- Essential for normal body function

- Key minerals:

- Calcium

- Phosphorus

- Chlorine

- Magnesium

- Potassium

- Sodium

- Sulfur

Gradients

- Represent differences between two points

- Types:

- Pressure gradients (blood pressure, air flow)

- Concentration gradients (chemicals)

- Electrical gradients (voltage)

- Thermal gradients (temperature)

- Matter and energy naturally flow down gradients

- Movement against gradients requires energy (ATP)

- Electrons in the outermost shell (valence shell) determine chemical properties and reactivity

- Electrons are attracted to protons in the nucleus

- Atoms can have multiple shells (1-4+)

- First shell can only hold 2 electrons

- Second and third shells follow octet rule - most stable with 8 electrons

- Elements with full outer shells are stable and less reactive

Isotopes and Atomic Structure

- Isotopes are different forms of same element with different numbers of neutrons

- Atomic number represents number of protons

- Atomic mass = protons + neutrons

- Atomic weight is average of element plus all its isotopes

- Most abundant elements in human body: Carbon, Hydrogen, Oxygen, Nitrogen (96%)

- Next most abundant: Calcium and Phosphorus

Radioisotopes and Radiation

- Radioisotopes are unstable isotopes that decay and release radiation

- All elements have at least one radioisotope

- Higher decay rates lead to higher radioactivity

- Types of radiation:

- UVA and UVB rays from sun

- Alpha and beta particles

- Gamma rays (most dangerous)

- X-rays

Radiation Measurement and Effects

- Measured in Sieverts (Sv)

- 5 Sv or more is usually fatal

- 50 mSv per year is acceptable exposure

- Natural background radiation ≈ 2.4 mSv/year

- Effects of radiation:

- Can be mutagenic (causes DNA mutations)

- Can be carcinogenic (causes cancer)

- Impact varies based on exposure type and metabolic rate

Half-Life

- Physical half-life: Time for 50% of radioisotope to decay

- Biological half-life: Time for 50% to leave body

- Biological impact affected by:

- Metabolic rate

- Method of elimination

- Age of person

Ions and Electrolytes

- Ions are charged atoms/molecules with unequal protons and electrons

- Types:

- Cations: positive charge (lost electrons)

- Anions: negative charge (gained electrons)

- Electrolytes:

- Ions that conduct electricity in water

- Critical for body function

- Imbalances can cause:

- Muscle cramps

- Cardiac arrest

- Seizures

- Coma

- Death

- Important for:

- Chemical reactions

- Water balance

- Nerve function

- Muscle function

Safety Considerations

- Monitor X-ray exposure frequency

- Use proper sun protection (UVA/UVB)

- Test basements for radon gas

- Limit close exposure to electronic devices

- Be aware of food sources exposed to radiation

Charles Darwin

- Recognized as the father of evolution for his groundbreaking research

- His work continues to influence multiple scientific fields including evolution, ecology, and genetics

- Developed the theory of natural selection, explaining how species change over time

Natural Selection

- Based on reproductive success and species adaptation over time

- Species evolve through inherited advantages passed to offspring

- Changes occur in genetic composition (DNA) of populations

- Driven by environmental factors and selection pressures including climate, food availability, and water access

Examples of Natural Selection

Peacock Evolution

- Male peacocks demonstrate sexual selection through elaborate, colorful feathers

- Developed over hundreds of years

- Female peacocks remain less colorful and choose mates based on coloration

- Males with more vibrant colors have greater reproductive success

- Similar patterns observed in birds of paradise with their mating displays

Wisdom Teeth

- Historically emerged in late teens or early twenties

- Modern humans often lack adequate jaw space due to improved dental hygiene

- Decreasing occurrence, particularly in Asian populations

- DNA for wisdom teeth remains present but less frequently activated

- Can cause complications when growing into jaw joint

Skin Color Adaptation

- Varies based on geographic location relative to the equator

- Darker skin near equator provides protection from harmful sun rays

- Lighter skin in regions far from equator enables vitamin D synthesis

- Determined by melanin production and accumulation, not melanocyte count

- Demonstrates balance between sun protection and vitamin D production needs

Climate Change and Evolution

- Climate change occurring faster than evolutionary adaptation

- Some species showing successful adaptation:

- Sharks adapting to new temperature zones

- Surviving in previously uninhabitable areas

- Other species struggling to adapt:

- Polar bears facing challenges due to melting ice

- Difficulty maintaining hunting patterns and reproductive success

- Risk of extinction for species unable to adapt

Selection Pressures

- Environmental factors drive evolutionary changes

- Success measured by ability to reproduce and pass on genetic traits

- Species must adapt to changing conditions for survival

- Climate change creating unprecedented pressure on species adaptation