Lecture 1- levels of organizations, feedback loops, Radiology, Sonograms

Chemical components

Fundamental chemical substances in the body (e.g., hydrogen, oxygen atoms and water) that compose matter.

Cell

The smallest independently functioning unit of life, containing a cell membrane, cytoplasm, and organelles.

Tissue

A group of similar cells that work together to perform a specific function.

Organ

An anatomically distinct structure composed of two or more tissue types that performs one or more physiological functions.

Organ system

A group of organs that work together to perform major functions or meet physiological needs.

Integumentary system

System including the skin and associated structures that protect the body and regulate temperature.

Skeletal system

Bones and joints; provides support, protection, and a framework for movement.

Muscular system

Muscles that produce movement and generate heat.

Nervous system

Network of nervous tissue that coordinates and integrates body activities.

Endocrine system

Glands that secrete hormones regulating body processes.

Cardiovascular system

Heart and blood vessels; circulates blood to distribute nutrients and remove wastes.

Lymphatic system

Transports lymph and defends against disease; returns excess fluid to blood.

Respiratory system

Lungs and airways; exchanges gases (O2 in, CO2 out).

Digestive system

Digestive tract and organs that break down food and absorb nutrients.

Urinary system

Filters blood to remove wastes and maintains fluid and electrolyte balance.

Reproductive system

Organs involved in producing offspring.

Metabolism

All chemical reactions in the body that store, release, and use energy.

Anabolism

Building up larger molecules; consumes energy.

Catabolism

Breaking down molecules; releases energy.

ATP

Adenosine triphosphate; the primary energy currency of the cell.

Homeostasis

Maintenance of a stable, steady internal environment in living organisms.

Set point

Normal range or target value for a physiological parameter.

Negative feedback loop

Counteracts a change, bringing the system back to equilibrium (homeostatis)

Sensor (receptor)

Structure that monitors a variable and detects deviations from the set point.

Control

Center that compares deviations to the set point and determines the corrective response.

Effector

Component that acts to restore the system to its set point.

Computed Tomography (CT)

Cross-sectional imaging using computers to process multiple X-ray slices for detailed anatomy.

Magnetic Resonance Imaging (MRI)

Imaging modality using magnetic fields and radio waves to produce detailed soft-tissue images; high cost and noise.

Positron Emission Tomography (PET)

Imaging using radiopharmaceuticals to study physiological activity (e.g., blood flow); relatively safe due to short-lived radiation.

Ultrasonography

Imaging using high-frequency sound waves to create real-time images; limited by bone and gas.

X-ray

high energy electromagnetic radiaton, short wave lengths, penetrates bones and solids. Soft tissues in gray, Bones in white

Positive Feedback Loop

amplifies a change, moving the system further away from equilibrium (homeostatis)

Positive feedback loops outcome

leads to a rapid change

Negative feedback loops outcome

maintains steady internal conditions