Human Body Systems Review

Human Body Systems

There are some organs that overlap between systems! Watch out for them! 

There are 11 major organ systems listed below, each corresponding to an organ system in a real body. They are listed below:

Circulatory System

The main role of the Circulatory System, also known as the Cardiovascular system is to transport nutrients and oxygen to the body. Think of the circulatory system as a “highway” of nutrients and oxygen. Some organs that this includes are:

• The Heart

  • Muscular, similar to a pump

  • Usually beats about 60 to 100 times per minute

  • Within each heartbeat, the heart sends blood throughout our bodies, carrying oxygen to every cell. During this leg of the journey, all of the blood cells are oxygenated. This blood is carried by arteries.

  • After delivering the oxygen, the artery flows into a capillary, and the capillary ends in a vein, the blood returns to the heart; it is now carrying deoxygenated blood. This blood is carried by veins.

  • The heart pumps the blood to the lungs to pick up more oxygen.

  • This cycle repeats over and over again.

• Blood Vessels

  • Pathways that carry blood throughout the body.

  • Arteries are vessels that carry blood away from the heart to the rest of the body. Arteries always carry oxygenated blood.

    • There is one exception: Pulmonary arteries carry blood from your heart to your lungs. They’re the only arteries in your body that carry oxygen-poor (deoxygenated) blood.

  • Veins are vessels that bring deoxygenated blood back to the heart. Veins always carry deoxygenated blood.

  • Capillaries Connect:

    • Capillaries connect arteries to veins.

    • They are the smallest blood vessels; 1 cell thick!

    • Oxygen, nutrients, and waste move easily through capillay walls to allow for flow in and out of the vessel.

• The Lungs

  • The lungs provide oxygen for the heart to transport to the body. More on the lungs in the Respiratory System!

Respiratory System

The respiratory system is a group of organs that work together to take in oxygen, and expel carbon dioxide from your body. The respiratory system and the circulatory system work closely together. More about the organs below:

• The Trachea

  • Also known as the WINDPIPE

  • Splits into 2 branches called bronchi (bronchus is the singular)

    • Each bronchus connects to each lung

    • Each bronchus branches into smaller tubes called bronchioles

    • Bronchioles branch into alveoli.

• The Diaphram

  • Dome-shaped muscle below the lungs.

  • When you INHALE, the diaphragm contracts & moves down, allowing air to come into the chest.

  • When you EXHALE, the diaphragm expands & moves up, helping force the ai from your chest.

  • A spasm of the diaphragm causes hiccups.

• The Lungs

  • A sponge-like organ

  • Transports oxygen from the air you breathe into your bloodstream

  • Removes carbon dioxide waste from the body when we exhale.

  • Jobs of the Lungs:

    • Deliver oxygen to the cells in your body.

    • Remove waste gases, including carbon dioxide, from the body when you exhale.

    • Protect your airways from harmful substances and irritants.

  • Gas exchange takes place inside the lungs. More specifically, in the alveoli.

• The Alveoli

  • Located inside the lungs, the bronchioles lead to alveoli, tiny sacs surrounded by blood vessels that allow for gas exchange to take place when we breathe.

  • Gases oxygen and carbon dioxide move across the thin walls of the alveoli and blood vessels.

• The Larynx (aka Voice Box)

  • Contains vocal chords

  • Produces the sound of your voice

  • Path of air: 

    • Nostrils/Mouth ➠ Throat (pharynx) ➠ Voice box (larynx), after this your voice should be heard, ➠ Windpipe (Trachea) ➠ Split into left and right lungs ➠ L+R Bronchial Tubes ➠ Alveoli ➠ Capillaries (very thin varrier lets oxygen enter blood here and carbon dioxide exit the blood here)

• Bronchial Tubes

  • Series of tubes that connect the throat to the lungs.

  • They become smaller as they travel deeper into the lungs.

  • LIKE BRANCHES ON A TREE!

Muscular System

The muscular system works closely with the skeletal system to move the body. It contains 3 types of muscle. Muscle is the tissue that contracts & relaxes, allowing movement. The muscular system also supports all major organs of the body and all organs are made up of muscle. Read more about the involved organs below:

• Types of Muscles

  • Skeletal Muscle

    • The only VOLUNTARY muscles

    • Meaning the only muscles we have to tell our bodies to move.

  • Smooth Muscle

    • Controls organs in our body without us having to think about it.

    • INVOLUNTARY muscle

    • Our stomach, liver and other organs are made of smooth muscle. 

  • Cardiac Muscle

    • The muscle in our heart that pumps our blood.

    • INVOLUNTARY muscle.

• Tendons & Ligaments

  • Tendons are strands of tissue that connect muscle to bone.

  • Ligaments are strands of tissue that connect bone to bone.

• Some Extra Facts

  • There are 650+ muscles in the body

  • Many muscles work in pairs, like biceps and triceps

Excretory System

The excretory system, also known as the urinary system, removes excess water and waste from the body. Read more about involved organs below:

• Kidneys

  • Pair of organs in the body that filter waste from blood and send it out of the body as urine.

  • Keep water level in body correct

  • Gets rid of wastes

  • Activates vitamin D

  • Makes sure blood pressure is in range.

  • Clean about 120 quarts of blood each day.

  • You can live with only one kidney, but you have to be extra careful. People are born with two kidneys.

• Urine

  • Waste filtered and removed from blood by the kidneys. It is stored in the bladder and excreted through the urethra.

  • Urine is 95% water.

• Uterus

  • Thin tubes that carry urine from the kidneys to the bladder.

• Bladder

  • Balloon-shaped organ that expands when it fills with urine.

• Urethra

  • A tube that transports urine from the bladder to outside of the body.

• Skin

  • The skin is also part of the excretory system, as it excreats waste through sweat.

Nervous System

The nervous system includes the brain, spinal chord, and a complex network of nerves. Think of it this way: Your body would be a nervous wreck without the nervous system. This system sends messages back and forth between the brain and the body. Read more about the organs involved below:

• The Brain

  • This organ is the control center of the body

  • Contains 3 main parts: cerebellum, cerebrum, and the brain stem

  • Constantly receives impulses from all over the body

  • Tells us how to act and react to sensory information

  • Think of it as a central computer that controls all the body’s functions

• Spinal Cord

  • The major highway to and from the brain

  • A long, tube-like band of tissue that carries nerve signals from your brain to your body & vice versa. These nerve signals help you feel sensations & move your body.

  • Like the internet of nerve signals! Its the ROUTE for all nerve signals traveling between the brain and the body.

• Nerves

  • Like cables that carry electrical impulses between your brain and the rest of your body.

  • These impulses help you feel sensations and move your muscles.

  • Also maintain certain functions like breathing, sweating, or digesting food.

  • Nerve cells are also called NEURONS

  • Pathways that send signals from one part of your body to another.

• Sense Organs

  • Includes ears, eyes, mouth, nose and skin

  • Each organ has special structures that collect information and send it to the brain through the nervous system.

• Central Nervous System: CNS

  • Includes the brain and the spinal chord

  • Body’s master control unit

  • Brain ⇝ specialized parts

  • Brain Stem ⇝ connects brain to spinal cord

  • Spinal Cord ⇝ column of nerves

  • It receives, processes, stores, and transfers information

  • The spinal cord allows information to be sent out and received by the brain.

• Peripheral Nervous System

  • The sensory organs and the nerves that branch from the central nervous system (CNS) to the rest of the body.

  • Has sensory and motor neurons that transmit information from the CNS to the rest of the body.

  • Receiving information is also called a stimulus. It starts with the sensory system which includes 5 senses.

  • Sensory system is part of your peripheral nervous system.

  • It detects or senses the environment. Humans use sense such as vision, hearing, smell, taste, and touch to detect the outside environment.

  • There are other senses such as sense of direction but we’re gonna focus on the 5 main ones

  • The Parasympathetic part of your automatic nervous system balances your sympathetic nervous system.

  • Sympathetic Nervous system controls “fight or flight” response.

  • Parasympathetic Nervous system helps to control your body’s response during times of rest, “rest & digest”

Skeletal System

The skeletal system works closely with the muscular system to move the body. It also provides structure and protection for the body. Read about the organs involved below:

• Bones

  • Bones are a living tissue that provides structure & support to the body.

  • Bones protect your organs & work with muscles to allow your body to move!

  • Bones store minerals such as calcium and magnesium

  • Bones are the site where red blood cells are made.

  • Bondes have blood vessels which supply nutrients and nerves that signal pain.

  • A grown human adult has 206 bones.

• Cartilage

  • A strong, flexible connective tissue that supports and protects bones.

  • Acts as a shock absorber throughout your body.

  • It’s bendable, not hard like bone and is found in various parts of your body, including between bones so they don’t rub together. The tip of your nose or the tip of your ear: that’s cartilage.

• Ligaments

  • A tough & fibrous tissue that connects two bones to form a joint

  • It is also a type of connective tissue.

  • Used to connect bone to bone

• Tendons

  • Strands of tissue that are used to connect muscle to bone.

Digestive System

The digestive system breaks down food to provide energy and nutrients to the body. A group of organs that break down food so that it can be used for energy, cell grown and repair. The system starts at the mouth and ends up at the anus where things that cannot be digested are pushed out as waste. Read more about the involved organs below:

• Mechanical & Chemical Digestion

  • Chewing is mechanical; digestion starts when your teeth break down food into smaller pieces that you can swallow.

  • Chemical digestion begins when the enzymes in the saliva begin to chemically break down the food.

• Mouth

  • Digestion starts when your teeth break food into smaller pieces that you can swallow.

• Salivary Glands

  • Make saliva which contains special enzymes that help digest the starches in your food (chemical change)

  • Also moistens your mouth and food

  • Sliva is a liquid produced by salivary glands that wets food and contains chemicals that bein to break it down.

• Tongue

  • The tongue helps move food as you chew and helps you swallow.

• Teeth

  • Teeth chew, breaking down food for swallowing.

  • This is a mechanical/physical action that creates a physical change ⤻ the food is being broken into smaller pieces.

  • There are 3 types of teeth:

    • Incisors

      • Used to cut food

    • Canines

      • Used to tear food

    • Molars

      • Used to grind food

• Peristalsis

  • Pattern of muscle contractions that move food through the esophagus and intestines.

  •   ⥢ A visual of peristalsis

• Esophagus

  • A tube that transports food from the mouth to the stomach.

  • This muscular tube is lined with mucus

  • In the process of peristalsis, muscles contract to move food from one end to another

    • Peristalsis moves food through the esophagus, stomach, and intestines.

  • When food goes in the wrong pipe, you gag and cough to get it out.

  • Your epiglottis is a small flap of tissue that covers the windpipe. When food is swallowed, this folds down to stop food from going into the lungs.

• Stomach

  • A muscly bag that breaks down chewed up food by squeezing and churning food along with digestive juices.

  • It is a muscle

  • Hollow organ

  • Mixes/breaks down food

  • Passes food to small intestine

  • Mixes food (mechanical churning is peristalsis) with acid & enzymes that continue to break food down.

  • The enzymes & acid cause chemical changes during digestion.

  • Two sphinchters seperate keep the stomach from overflowing into the esophagus (Lower Esophageal Sphincter {L.E.S.})and spilling into the small intestine. 

• Small Intestine

  • Absorbs nutrients from the fod

  • Food spends 1 - 2 days traveling through the small intestine.

  • Soft winding tube where nutrients from food pass into the bloodstream.

  • Contains 3 parts

    • Duodenum

      • Lined with structures called VILLI that look like tiny fingers and allow nutrients & water to pass through intestinal walls.

    • Jejunum

      • Make up most of the small intestine, along with the Ileum, which is 6 meters long. Also has villi along their walls to absorb nutrients and water.

    • Ileum

      • Make up most of the small intestine, along with the Jejunum, which is 6 meters long. Also has villi along their walls to absorb nutrients and water.

  • Remember these 3 parts using D.J. I.van

• Large Intestine

  • Last part of the digestive tract where water is absorbed and remaining waste is stored as feces.

  • Water and Vitamin K are absorbed from food that passes through the large intestine. Bacteria help break down fiber and other materials.

  • The main job of the large intestine is remove water.

  • The appendix is a small useless flap of tissue attached to the large intestine. It has no particular use, but if it bursts, it can be deadly.

• Rectum

  • Where feces is stored before it is elimated through the anus.

• Anus

  • Where the digestive system comes to an end.

  • Poop 💩

• Accessory Organs

  • Liver

    • Process the nutrients absorbed from the small intestine; the villi absorb the nutrients and send them in the bloodstream, where they are shipped to the liver, which processes the nutrients.

    • Makes bile to help the body absorb fat 

    • Helps eliminate cholesterol

    • Liver is also the largest and heaviest internal organ in the body and it has lots of functions and has uses in many different organ systems.

• Gallbladder

  • Bile created in the liver is stored in a small bag called the gallbladder. Bile is a green liquid passed to the small intestine to help digest fat.

  • Stores a chemical called bile, which is produced by the liver.

  • Bile helps break up large fat globules into much smaller particles called fatty acids.

  • Fatty acids are the building blocks of that fat in our bodies and in the food we eat.

  • During digestion, the body breaks down fats into fatty acids, which can then be absorbed into the blood.

• Pancreas

  • Long, flat gland behind the stomach that produces enzymes and hormones. It helps break down carbohydrates, fats and proteins.

  • Produces digestive enzymes and hormones

  • These enzymes also break down carbohydrates, proteins, and fats.

  • The pancreas also produces an alkaline solution that neutralizes acid.

  • The pancreas puts its juices into the duodenum to help break down the food.

  • Also produces insulin, the hormone that regulates blood sugar.

Integumentary System

This system is the first line of protection coverin the body. It includes the skin, hair, & nails. As part of the immune system, the skin acts as a barrier that protects the body from infection. Read about the following organs involved:

• Skin

  • The skin is your largest organ, internal and external.

  • Provides external protection against pathogens that may enter the body.

  • Glands in your skin secrete oil that can kill pathogens. The skin’s mcus & saliva also provide protection.

  • Skin has 3 layers:

    • Epidermis, contains cells that produce pigment and protect immune system.

    • Dermis, contains nerve endings, oil, sweat glands, and hair follicles

    • Subcultaneous tissue (Hypodermis), made up of fat, connective tissue and larger blood vessels.

• Hair

  • Eyelashes and ear hairs keep many particles in the air from entering the body

• Nails

  • Protect your fingertips & toes

Immune System

The immune system protects your body by identifying and destroying pathogens like viruses, bacteria, parasitic works, protists, fungus, & any protein/substance that appears foreign or harmful.

 ★ ★ ★ The immune response is how your body recognizes & defends itself against bacteria, viruses, & substances that appear foreign & harmful.

• Your skin is the first line of defence against the pathogens.

• The immune system is made up of specialized white blood cells that recognize & attack foreign substances.

• The body builds immunity (the ability to resist or recover from an infectious disease) against a disease when it is exposed to the pathogens that cause the diease.

• There are 3 main lines of defence:

1. Physical barrier: mucus & skin

2. Immune response: fighting the pathogen directly

3. Antibodies

• The Immune system is a combo of body defences made up of the cells, tissues, and organs that fight pathogens in the body.

• The immune system’s main function is to protect the body from pathogens.

  • A pathogen is an agent that causes disease.

  •  A bacterium, virus, or another type of microorganism are examples of pathogens.

• White blood cells, also known as lymphocytes identify pathogens.

• Phagocytes, made in bone marrow, attack and kill pathogens.

Lymphatic System

This is the last system. The Lymphatic system is a group of organs and tissues that collect the fluid that leaks from blood and returns it to the blood. The leaked fluid is called lymph.

*** The Lymphatic System is part of your immune system.

• They lymphatic system is an open circulatory system, & lymph can move in and out of the blood vessels.

• The lymphatic system is also part of the body’s defense against disease.

  • Think lymph nodes, filters that remove germs that could harm you. They can swell when you are ill. This is why a doctor might feel the side of your neck.

• Your lymphatic system produces & releases Lymphocites and other immune cells. These cells look for & destroy invaders - such as bacteria, viruses, parasites, and fungi - that may enter your body.

Endocrine System

This system is in charge of secreting hormones that regulate body metabolism, growth, and reproduction. It is a system made up of glands that make hormones. Hormones are the body’s chemical messengers. They carry informations & instructions from one set of cells to another. This system influcnes almost every cell, organ, & function of our bodies. 

 ★ ★ ★ It helps maintain homeostasis!

Read more about the involved organs below:

• Glands

  • An organ which produces & releases substances called hormones that perform a specific function in the body.

  • Endocrine glands are ductless glands & release the substances that they make, hormones, directly into the bloodstream.

  • A gland is a group of cells that make special chemicals for your body.

• Hormones

  • The body’s chemical messengers.

  • Produced by the endocrine glands (see above)

  • Hormones travel through the bloodstream.

  • They travel from the endogrin gland where they are made and can reach every cell in the body.

  • Hormones affect only the cells that have specific  receptors. Each hormone has its own receptor and affects only cells that have that receptor. These cells are called target cells.

⋆｡°✩⋆｡°✩⋆｡° ☆ What does the endocrine system do when scared?

It alerts the hypothalamus, which sends a message to the adrenal glands to give you an instant burst of adrenaline, the “action” hormone. Adrenaline causes your heart to race & pump more blood to your muscles.