1122 The human body

Principle of complemetary function

Form determines function; Anatomy studies the structure of body parts and their relation to each other, Physiology studies the function of the body, how it all works to carry out all our essential processes

Gross Macro Anatomy

Study of large body structures visible to the naked eye (heart, lungs, kidneys for ex)

Microscopic Anatomy

Study of structures too small to be seen with the naked eye

Atoms

tiniest building blocks of matter ➢ Combine to form molecules (such as water & proteins)

Molecules

form organelles (components of cells

Cells

the smallest unit of life/living things ➢ Can vary in size and function giving them unique presentation/capabilities

Tissue

groups of cells with similar functions

Organs

formed by similar/ more than one tisues

Organ sytems

more than one organ working together to perform a function

Common set of chemical compounds that compose cells

1. Carbohydrates 2. Fatty acids 3. Nucleic acids 4. Amino acids

Nervous Tissue

Provides means of rapid internal communication through electrical signals • Ex Neuron

Muscle Tissue

Provide movement • Ex Biceps

Connective Tissue

Provides support & protection • Ex Bone and cartilage

Epithelial Tissue

Covers the body surfaces and line cavities

Most organs include

all 4 tissues

What are requiremnets for life?

• Maintain boundaries • Move • Respond to environmental changes • Take in nutrients for energy • Remove waste, eliminate toxins • Build all internal structures • Replenish and grow • Reproduce • Maintain constant conditions

Maintaining Boundaries

Protection: Must keep the inside separate from the outside

• Whole body • Integumentary system (skin) protects internal organs from: drying out, infection, damage from outside elements, temps, sunlight, etc… • At the cellular level • Cellular membrane/plasma membrane • Separates intracellular from extracellular

Interstitial Fluid

clear liquid that fills the spaces around and between cells in the body

contractility

the muscles' ability to shorten

Responsiveness

Also called excitability is the ability to sense changes (stimuli) in the environment, and react/respond to them • Examples: • Reflexes: do not require thought, they just happen without your awareness; Nervous System is most involved in sensing and reacting to these changes

Digestion

Breaking down of ingested food into simple and usable molecules, for all of life's processes

Excretion

• Process of removing waste/biproducts • Includes digestive system, urinary (renal) system & respiratory system

Metabolism

Metabolism is the continuous set of life-sustaining chemical reactions in the body that convert food and drink into the energy needed to power basic functions, grow, and repair cells. Largely regulated by hormones (secreted by the endocrine system) • Includes all chemical reactions, within your body’s cells

Catabolism

Breaking down substances into simple building blocks, pathways are those that generate energy by breaking down larger molecules.

Anabolism

Synthesizing more complex molecules from simple building blocks, pathways are those that require energy to synthesize larger molecule

Cellular respiration

Using nutrients and oxygen to produce ATP (Energy)

Anabolic and Catabolic pathways

*Both types of pathways are required for maintaining the cell’s energy balance

Reproduction

• Occurs at the cellular level • Original cell divides, produces identical daughter cells • Sperm + egg = zygote • Regulated by endocrine system, hormones

Growth

• Also involves cell division • Increase in size of an organisms • Constant repair of cells throughout life

Survival Needs

The goal of all body systems is to maintain life (Not so easy – very delicate) Several factors “survival needs” are required: Nutrients, Oxygen, Water, Normal Body Temperature, Appropriate Atmospheric Pressure.

Not enough to just have these needs, but also at the most appropriate and perfect amount/balance.

Nutrients

Taken in from food, use for energy and building blocks of cells

Oxygen

All chemical reactions of the body are oxidative, require oxygen to release energy

Water

We are 50-60% water, provides necessary environment for all cells and chemical reactions

Normal Body Temperature

Metabolic reactions, protein function only at ideal temp, 97°F to 99°F (36.1°C to 37.2°C)

Appropriate Atmospheric Pressure

Required for breathing, gas exchange will not occur at certain pressures

Homeostasis

the ability to maintain relatively stable conditions despite continuous changes outside, endocrine and nervous system are the big players

Nervous System & Endocrine System

Activities of physiological systems are controlled (speed up or slow down) by ____ _____through chemical and electrical signals

Set point

A reference point (where we wants things to be = optimal condition)

Receptors

• Sensors monitors and detects detect changes in the environment • Responds to stimuli, then sends message to the control center

comparator

compares to value of set point

Effectors

Muscles or glands that effect changes in the internal environment Also called controlled systems

Negative feedback

counteracting response to keep homeostasis • “negate the change” • Ex: temp, BP, pH

Positive feedback

intensify and amplify • Ex: contractions during labor, lactation, clotting/platelets

Thermoregulation

the biological process that allows an organism to maintain its internal core body temperature within a safe, narrow range

To increase Body Temp

• Vasoconstriction (avoid loss of heat) • Shivering, muscles produce heat with quick repetitive contract and relax

To decrease body Temp

Vasodilation ( send more blood to skin surface, lose heat through skin) • Sweating (evaporating sweat cools the skin)

Homeostatic Imbalance

• Loss of homeostasis would ultimately lead to death • As we age, our sensory and control systems become less efficient in maintaining homeostasis • Therefore, our body becomes less and less stable, leading to more damage & disease • Other instances of homeostatic imbalance are the results of damage to the negative feedback loop (disease)

Problem with Feedback systems: Disease Processes

• Diabetes • Without insulin – you are unable to change back toward set point of glucose • Some cardiac conditions • Tumors (ie hypothalamus) • Aging process – deterioration of receptors, regulators, etc

Anatomical Position

• The body is erect • Feet are slightly apart • Palms are anterior (facing forward) • Thumbs are lateral (pointing away from the body – outward)

X- rays

Short wavelength electromagnetic waves • 2 dimensional • Dense structures appear as light/whitish areas • Bones • Hollow organs and fat appear as dark areas • Used for detecting: • Fractures, tumors, measure density of bones • Not for detecting soft tissue damage (exceptions with contrast, barium) • Radiation risk

CT scans (Computed Tomography Scans)

Computerized reconstruction of a series of X-ray images taken from different angles • Cross-sectional images (slices) of the bones, blood vessels and soft tissues inside your body • Good for viewing: • Bones, soft tissue, blood vessels • Not ideal for: • Nervous tissue, joint structure • More radiation than x-rays

MRI (Magnetic Resonance Imaging)

Uses powerful magnets and radio waves • Distinguishes body tissue based on water content (specifically their hydrogen atoms) • Low water content structures (ie bones) not as visible, therefore really produces high contrast images of soft tissue • Used for: • Brain, spinal cord, nerves, joints (ligament, cartilage, tendons) • Cons: expensive, slow , cannot be used with metal

Ultrasound (Sonogram)

• High frequency sound waves that reflect (echo) off of the body's tissue • Able to monitor movement in real time (ie fetus, heart valve motion, blood flow) • Pros: inexpensive, no radiation • Used for: • Fetal monitoring during pregnancy • Gall stones • Blood vessel and valve disorders • Not for: air filled structures, or those surrounded by bone • Less resolution • Also used therapeutically in addition to diagnostically

PET scan (Positron Emission Tomography)

• Radioactive tracer molecules injected into body (different types of tracer depend on what they are looking for) • Reveals biochemical or metabolic functions of tissue “lights up” • Often combined with CT scans for even greater resolution/clarity • The tracer will collect in areas of the body that have higher levels of metabolic or biochemical activity. (therefore can see abnormality) • Ex: tumors use more glucose • Used for: detecting cancer, Alzheimers disease, overall brain function • High degree of radiation