teas

Cell

Basic unit of life

Organelle

Structure inside a cell with a specific function

Nucleus

Stores DNA and controls cell activities

Mitochondria

Produces ATP (energy)

Ribosomes

Make proteins

Rough ER

Protein synthesis and transport

Smooth ER

Lipid synthesis and detoxification

Golgi apparatus

Modifies, packages, and ships proteins

Lysosome

Breaks down waste

Cell membrane

Controls what enters and leaves the cell

Diffusion

Movement of molecules from high to low concentration

Osmosis

Diffusion of water

Active transport

Movement requiring energy (ATP)

Mitosis

Cell division for growth and repair

Meiosis

Cell division for gametes (sex cells)

Homeostasis

Maintaining stable internal conditions

Negative feedback

Body reverses a change to maintain balance

Epithelial tissue

Covers and lines surfaces

Connective tissue

Supports and binds (bone, blood, cartilage)

Muscle tissue

Movement (skeletal, smooth, cardiac)

Nervous tissue

Sends electrical signals

Main function of respiratory system

Gas exchange

Where gas exchange occurs

Alveoli

Muscle responsible for breathing

Diaphragm

Inhalation

Diaphragm contracts and moves down

Exhalation

Diaphragm relaxes and moves up

Air pathway

Nose → pharynx → larynx → trachea → bronchi → bronchioles → alveoli

Surfactant

Prevents alveoli from collapsing

Breathing control center

Medulla oblongata

Gas from alveoli to blood

Oxygen

Gas from blood to alveoli

Carbon dioxide

Hyperventilation effect

CO₂ drops, pH rises

Hypoventilation effect

CO₂ rises, pH drops

Main function of cardiovascular system

Transport blood, nutrients, gases, waste

Heart muscle type

Cardiac muscle

Right side of heart pumps to

Lungs

Left side of heart pumps to

Body

Strongest chamber

Left ventricle

Arteries carry blood

Away from heart

Veins carry blood

Toward heart

Capillaries

Site of gas and nutrient exchange

SA node

Heart pacemaker

Pulmonary arteries

Carry deoxygenated blood to lungs

Pulmonary veins

Carry oxygenated blood to heart

Systole

Heart contraction

Diastole

Heart relaxation

Blood flow through heart

Vena cava → RA → RV → pulmonary arteries → lungs → pulmonary veins → LA → LV → aorta

Hemoglobin

Protein that carries oxygen

Platelets

Blood clotting

Plasma

Liquid portion of blood

Main function of digestive system

Break down food and absorb nutrients

Mechanical digestion

Physical breakdown (chewing)

Chemical digestion

Enzyme breakdown

Mouth enzyme

Amylase (breaks down carbs)

Stomach enzyme

Pepsin (breaks down proteins)

Small intestine

Main site of nutrient absorption

Large intestine

Absorbs water

Liver

Produces bile

Gallbladder

Stores bile

Pancreas

Produces digestive enzymes and bicarbonate

Peristalsis

Wave-like muscle contractions moving food

Main function of endocrine system

Hormone regulation

Pituitary gland

Master gland

Hypothalamus

Links nervous and endocrine systems

Thyroid

Controls metabolism

Adrenal glands

Produce adrenaline and cortisol

Insulin

Lowers blood glucose

Glucagon

Raises blood glucose

Negative feedback in hormones

Maintains balance

Main function of nervous system

Communication via electrical signals

Central nervous system

Brain and spinal cord

Peripheral nervous system

All other nerves

Neuron

Nerve cell

Synapse

Gap between neurons

Neurotransmitter

Chemical messenger

Somatic nervous system

Voluntary movement

Autonomic nervous system

Involuntary functions

Sympathetic nervous system

Fight or flight

Parasympathetic nervous system

Rest and digest

Cerebrum

Thinking and voluntary movement

Cerebellum

Balance and coordination

Brainstem

Breathing and heart rate

Main function of skeletal system

Support, protection, movement

Main function of muscular system

Movement

Types of muscle

Skeletal, smooth, cardiac

Tendons

Connect muscle to bone

Ligaments

Connect bone to bone

Osteoblasts

Build bone

Osteoclasts

Break down bone

Axial skeleton

Skull, spine, ribs

Appendicular skeleton

Limbs

Sliding filament theory

Actin and myosin cause muscle contraction

Main function of immune system

Fight infection

Innate immunity

Fast, non‑specific

Adaptive immunity

Slow, specific

Antibodies

Proteins that target pathogens

White blood cells

Fight infection

Lymph nodes

Filter lymph

Spleen

Filters blood

B cells

Produce antibodies