Bio 252- Chapter 1 Study Guide

I. Know the definitions of anatomy and physiology.

Anatomy is the study of the structures of living organisms.

Physiology is the study of how living organisms function.
II. Understand the relationship between form and function.

The relationships between form and function is the body has multiple levels of organization. At each level, the function (Physiology) is related to the structure (anatomy) III. Levels of Human Structure – Understand what each of these levels refer to.
A. Chemical Level- Atoms combine to form molecules. Some molecules, such as water, are simple. Others such as carbohydrates, lipids. and proteins, are large and complex.
B. Organelle/Cellular Level- Molcules combine to form organelles which help to form the basic structure of cells. Cells are the basic structural and functional units of organisms and of life.

C. Tissue Level- A tissue is a group of similar cells and the material surrounding them. The four primary types of tissues are: Connective, Epithelial, Muscle, Nervous.
D. Organ Level- An organ is a structure composed of two or more types of tissue that work together to carry out a particular function or group of functions.
E. Organ Systems Level- An organ system consists of two or more organs working together for a common function or set of functions. A single organ can belong to more than one organ system (e.g. the pancreas).
F. Organismal Level- The structures and functions of organ systems are integrated to form a single, complete individual.
IV. Understand that there is anatomical variation amongst individuals. Be able to provide some
examples.

NO TWO HUMANS ARE EXACTLY ALIKE- Anatomy books show the most common and most likely organization of structures.

Some individuals lack:

  • Lack Certain muscles

  • atypical number of vertebrae

  • exhibit situs inversus- a left-right reversal or organ placement.


V. Remember to read Deeper Insight 1.2- Situs Inverse and the Other Unusual Anatomy:

- Normal Anatomy (Situs Solitus):

- Most people have the panc. reas, sigmoid colon, and most of the heart on the left side.

- The appendix, gallbladder, and most of the liver are typically on the right side.

- This standard arrangement of internal organs is called situs solitus.

- Situs Inversus:

- About 1 in 8,000 people are born with a condition called situs inversus, where the organs of the thoracic (chest) and abdominal cavities are reversed, with left and right sides swapped.

- Despite this reversal, people with complete situs inversus usually have no functional health problems because their organs maintain the correct relationships to each other.

- Dextrocardia:

- Dextrocardia is a condition where only the heart is reversed to the right side, without the other organs being reversed.

- Dextrocardia without complete situs inversus can cause serious medical issues.

- Situs Anomalies and Medical Considerations:

- Conditions like a kidney located unusually low in the pelvic cavity or high in the abdominal cavity are examples of unusual organ placement (situs anomalies).

- Situs inversus is often discovered during a prenatal ultrasound but can remain unnoticed for decades until found during medical imaging, physical exams, or surgery.

- Medical Implications:

- Situs inversus is important to consider when diagnosing appendicitis, performing gallbladder surgery, interpreting X-rays, listening to heart valves, or reading an electrocardiogram (ECG).

Deeper Insight 1.3- Men in the Oven

• Charles Blagden (1748-1820):

• An English scientist who demonstrated homeostasis before the term existed.

• 1775 Experiment:

• Blagden spent 45 minutes in a room heated to 127°C (260°F) with a dog, beef steaks, eggs, and some fellow researchers.

• What Happened:

• The beef steaks, unable to regulate temperature, were cooked in about 13 minutes.

• The eggs were fully cooked (hard-boiled) in 47 minutes.

• Blagden, the other men, and the dog survived by cooling themselves through sweating and panting.

• Body Temperature:

• Despite the extreme heat, the men’s body temperatures stayed between 37°C and 38°C (98°F to 100°F), showing their bodies maintained homeostasis.

• They noticed the air felt cooler each time they exhaled, which helped with cooling.

• Outcome:

• Everyone, including the dog, survived the experiment, though history doesn’t say whether they celebrated by eating the steak.

Deeper Insight 1.4- Obscure Medical Word Orgin

The literal translation of a word often doesn’t reveal its modern meaning due to the complex history of language. This can be confusing for learners. Here are a few examples:

  • Amnion: This term refers to the protective sac around a developing fetus. It comes from the Greek word "amnos," meaning "lamb." Initially, "amnos" was used for a bowl that caught the blood of sacrificial lambs. Over time, the term shifted to describe the sac that emerges during childbirth.

  • Acetabulum: This is the socket of the hip joint. The Latin word "acetabulum" means "vinegar cup" because the shape of the hip socket reminded ancient anatomists of small cups used for serving vinegar.

  • Testicles: This word can be translated as "little pots" or "little witnesses." The reasons behind why this term was chosen for the male gonads are both interesting and sometimes amusing.

These examples show how the history of language can lead to meanings that are quite different from their original translations.

Deeper nsight 1.5- Medical Imaging

Medical imaging has revolutionized how we look inside the body without needing surgery, greatly advancing medicine. Here are some key imaging techniques:

  • Radiography: Introduced in 1895, radiography uses X-rays to capture images of internal structures. X-rays pass through soft tissues but are absorbed by denser materials like bones and tumors, creating lighter images in those areas. It's widely used in dentistry, mammography, and diagnosing fractures. A special technique, digital subtraction angiography (DSA), helps visualize blood vessels by taking X-rays before and after injecting a contrast medium, which highlights blockages and other issues. However, radiography can cause cancer and birth defects due to X-ray exposure.

  • Computed Tomography (CT): CT scans are an advanced application of X-rays. A patient moves through a machine that takes X-ray slices of the body, which a computer then combines to create detailed cross-sectional images. CT is excellent for identifying tumors, aneurysms, and kidney stones but requires a good understanding of anatomy to interpret.

  • Magnetic Resonance Imaging (MRI): MRI uses a powerful magnet and radio waves to create detailed images of soft tissues. It's particularly good for visualizing the brain and spinal cord and distinguishing between different types of soft tissue. MRI does not use X-rays, avoiding related risks, but can be uncomfortable due to noise, claustrophobia, and long scanning times. Open MRI machines are available but offer lower image quality.

  • Functional MRI (fMRI): A type of MRI that measures brain activity by detecting changes in blood flow. It provides insights into brain function and has largely replaced PET scans for studying brain activity.

  • Positron Emission Tomography (PET): PET scans assess the metabolic state of tissues using a radiotracer (radioactive glucose). It highlights areas of high activity and is useful for diagnosing cancer, evaluating heart damage, and detecting Alzheimer's disease. PET scans are generally low resolution but valuable for early diagnosis and monitoring.

  • Sonography (Ultrasound): This method uses high-frequency sound waves to produce images of internal organs. It’s widely used in obstetrics to monitor fetal development and in cardiology to examine heart function. Sonography avoids X-ray risks and is portable but is less effective for imaging bones or producing very sharp images.

These imaging techniques each have their strengths and limitations, but together they provide a comprehensive view of the body’s internal structures and functions.