Body Systems

Comprehensive vocabulary flashcards covering the Nervous, Endocrine, Respiratory, Circulatory, Digestive, and Excretory systems based on the lecture notes.

Nervous System

Provides rapid, short-term control and communication throughout the body using electrical and chemical signals. Main control and communication network

Endocrine System

Provides slower, long-term regulation of body processes like growth, metabolism, and mood using chemical messengers in the blood.

Hormones

Chemical messengers produced by endocrine glands that travel in the blood to regulate target cell/organ functions.

Central Nervous System (CNS)

Consists of the brain and spinal cord; processes information and makes decisions.

Peripheral Nervous System (PNS)

All nerves outside the CNS; connects the CNS to limbs, organs, and sensory receptors. eg Ganglia, Cranial and Spinal nerves

Action Potentials

Electrical impulses that travel down the axon within a neuron.

Neurotransmitters

Chemicals triggered for release across the synapse to bind to receptors on the next neuron.

Dendrites

Neuron structures that receive incoming signals.

Soma (Cell Body)

Contains the nucleus and maintains the neuron cell.

Axon

Transmits electrical impulses away from the soma.

Myelin Sheath

An insulating fatty layer around axon that speeds up signal conduction in a neuron. Keeps the signal strong

Axon Terminals

Release neurotransmitters into the synapse.

Sensory Neurons

Carry impulses from sensory receptors to the CNS.

Interneurons

Neurons within the CNS that connect sensory and motor neurons and process information.

Motor Neurons

Carry impulses from the CNS to effectors, such as muscles or glands, to trigger action.

Cerebrum

Responsible for higher executive function, conscious thought, memory, reasoning, and voluntary movement.

Frontal Lobe

The lobe of the cerebrum responsible for decision making, planning, motor control, and speech.

Parietal Lobe

The lobe of the cerebrum responsible for processing tactile/sensory information like touch, temperature, and pain.

Occipital Lobe

The lobe of the cerebrum responsible for vision processing.

Temporal Lobe

The lobe of the cerebrum responsible for hearing, language comprehension, and memory.

Corpus Callosum

A thick band of nerve fibers connecting the left and right cerebral hemispheres.

Cerebellum

Responsible for balance, posture, and coordination of fine motor skills.

Medulla (Brainstem)

Controls autonomic/involuntary vital functions including breathing, heart rate, and blood pressure.

Reflex Arc Pathway

The route taken by a reflex action: $Receptor \rightarrow Sensory Neuron \rightarrow Interneuron (Spinal Cord) \rightarrow Motor Neuron \rightarrow Effector (Muscle/Gland)$.

Homeostasis

The maintenance of a stable internal environment, such as temperature or blood glucose.

Negative Feedback Loop

Reverses a change to return the system to its set point to maintain stability, such as sweating to cool down.

Positive Feedback Loop

Amplifies or reinforces a change away from normal until an outcome is reached, such as oxytocin release during childbirth.

Cellular Respiration Equation

$$Glucose + Oxygen \rightarrow Carbon Dioxide + Water + ATP (Energy)$$

Respiratory System

Responsible for gas exchange by absorbing $O_2$ and excreting $CO_2$.

Circulatory System

Transports nutrients, gases, hormones, and waste throughout the body.

Digestive System

Breaks down food into absorbable nutrients and expels solid waste.

Excretory System

Removes metabolic waste products and excess fluids from the body.

Amylase

breaks down carbohydrates/starches into simple sugars.

Protease (e.g., Trypsin)

breaks down proteins into amino acids.

Lipase

breaks down fats into fatty acids and glycerol.

Kidneys

Part of the urinary system that excretes urea, excess water, and salts via producing urine

Liver

Main organ that produces bile, detoxifies chemicals, processes nutrients, and converts ammonia into urea.

Arteries

Carry oxygenated blood away from the heart under high pressure, with the exception of the pulmonary artery.

Veins

Carry deoxygenated blood towards the heart and contain valves to prevent backflow.

Capillaries

Microscopic, thin-walled vessels where gas and nutrient exchange occurs with tissues.

Gallbladder

Stores and concentrates bile before releasing it into the small intestine.

Pancreas

Produces digestive enzymes and bicarbonate to neutralize stomach acid, and secretes insulin and glucagon.

Messages move along a neuron

Catching Signals
Dendrites catch signals: Tiny branch-like parts on the neuron get chemical or physical signals from nearby cells.

• Cell body decides: The main cell body gathers these inputs. If the signal is strong enough, it triggers an impulse. [1, 2, 3]

Passing the Electrical Message Inside the Neuron

• Action potential starts: A fast change in electrical charge moves down the axon (the long tail of the neuron).

• Ions move: Sodium and potassium particles rush in and out of tiny gates in the cell wall, creating a moving wave of electricity. [1, 2, 3]

Crossing to the Next Cell

• Reaching the end: The electrical wave reaches the end of the axon (the axon terminal).

• Releasing chemicals: Tiny sacs release chemical messengers called neurotransmitters into a small gap called the synapse.

• Next cell responds: The chemicals stick to receptors on the next cell, starting a new electrical signal there.