Science Body Systems Generic Review 7th Grade

Science Body Systems Unit 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.

Plant Systems

Now that we’ve covered humans, let’s move on to plants. Here we will be observing plant systems to see how they work.

Heirarchy of Biological Organization

*** The hierarchy of biological organization, from simplest to most complex, includes atoms, molecules, organelles, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystems, and the biosphere. But we will only focus on cells, tissues, organs, organ systems, and organisms.

*** This organization is the same for plants and animals. They just look different.

Importance of Cells

EVERY LIVING THING IS MADE OF CELLS!!!

• The larger the organism, the more cells. The smaller the organism, the less cells.

• Scientists estimate that there are 37.2 trillion cells in the human body (37,200,000,000,000).

• All cells are organized.

• As multicellular organisms grow, cells divide to produce/make new cells.

• The first cells made can become any type of cell (these are stem cells)

Thus, cell differentiation.

Cell Differentiation

*** Cell differentiation is the process by which cells become different types of cells.

• Animal (stem) cells can become muscle cells, nerve cells, blood cells, bone cells, or skin cells. But they might also specialize to function for the organism’s needs.

• Plant (stem) cells can become specialized cells as well.

*** Cell differentiation also takes place in plants.

• However, plants have different types of cells with specialized structures & functions.

• They make food, store food, protect the plant, or transport materials.

• These cells might become parts of stems, leaves, flowers, or roots.

Animal Tissue Types

Remember that all organs are made up of tissues? Let’s take a look at different types of tissues.

*** An organ is a group of different tissues working together to perform a particular job.

For example, take the animal heart.

There are four different types of tissues found in the body.

• Muscle Tissue – cardiac muscle, smooth muscle, & skeletal muscle. (these were covered in muscular system earlier on)

• Epithelial Tissue – the skin surface & lining of the GI tract organs, plus other hollow organs like bronchioles & fallopian tubes.

• Nervous Tissue – nervous tissue of the brain, spinal cord & nerves

• Connective Tissue – fat, bone & tendon. Blood is a specialized connective tissue!

Let’s take a look at how they work specifically in the heart.

❤Muscle Tissue pumps blood out of the heart to the rest of the body.

❤Epithelial Tissue lines blood vessels. This allows blood to flow smoothly through the organ.

❤Nervous Tissue controls the beating of the heart.

❤Connective Tissue is found in the walls of blood vessels.

Plant Tissue Types

There are 2 divisions of plants.

• Vascular plants

  • Like Angiosperms are vascular plants that produce flowers and make their seeds in fruit. *They are the largest and most diverse group within the kingdom Plantae, with about 300,000 species.

  • Gymosperms are vascular plants that have exposed seeds, or ovule – unlike angiosperms, or flowering pants, whose seeds are enclosed by mature ovaries or fruits. Conifers, trees with cones, are the largest group of these. Ginkgo trees and their round trees are also included.

  • Ferns are vascular plants that reproduce via spores & have no seeds or flowers.

• Non-Vascular Plants

  • Don’t have tubelike tissues to move water and food.

  • They don’t have true stems and leaves.

  • Example: moss

There are 3 types of tissue in plants.

• Dermal Tissue

  • Covers the outer surface of a leaf, (epidermis for humans)

  • Helps to minimize water loss (similar function to our skin)

  • Stomata located here

  • Has lateral outgrowths called root hairs.

• Ground Tissue

  • The leaf contains ground tissue that produces food for the rest of the body. This makes the leaf a vital organ.

  • Makes up most of the plant interior

  • Has different kinds of tissue

  • Help with storage, and photosynthesis takes place in the ground tissue, more specifically, in the chloroplast.

• Vascular Tissue

  • Moves water, as well as the food produced by photosynthesis, throughout the leaf and the rest of the plant.

  • Transports water and nutrients from one part of a plant to another

  • Comprised of the xylem and the phloem, the main transport systems of plants.

• Xylem and Phloem Tissues

  • Xylem Tissue

    • Transport water and minerals from the roots to the stems and leaves.

    • Comprised of hollow tubes.

  • Phloem Tissue

    • Transport dissolved sugars from the leaves to the rest of the plant for use or storage.

    • Composed of elongated walls which contain pres in their end walls to allow cell sap to move from one phloem cell to the next.

Similarities and Differences Between Plants and Animals

There are lots of similarities between plants and animals, such as the need of glucose/sugars, oxygen and carbon dioxide, the need to excrete waste, and absorption of nutrients.

• Gas Exchange

  • Humans

    • This happens in the lungs of humans. More specifically, in the alveoli.

  • Plants

    • This happens in the leaves of plants. More specifically, the stomata. Therefore, leaves are like the “lungs” of plants. And stomata are like the “alveoli” of plants.

    • Plants also conduct transpiration through the leaves. Think of this like “sweating” plants.

  • Stomata

    • The “alveoli” of plants.

    • Transpiration occurs here.

    • Plants also excrete waste (like carbon dioxide, oxygen, and excess water)

    • Allow gas exchange 

    • Protected by a pair of bean-shaped guard cells that regulate its opening and closing.

• Xylem & Phloem vs Blood

  • Humans

    • Blood is the highway for all nutrients, gases and hormones. It carries things to and from the body.

  • Xylem only moves water and ONLY MOVES UPWARDS.

  • Phloem moves food and MOVES BOTH WAYS

• Tissue Types

  • Humans:

    • 4

      • Epithelial – lines organs

      • Connective – fat, bone, & tendon, INCLUDING BLOOD

      • Nervous – nervous tissue (this should be obvious)

      • Muscle – Cardiac, smooth, and skeletal.

  • Plants:

    • 3

      • Dermal – outer surface

      • Ground – PHOTOSYNTHESIS occurs here, and its pretty much everything that’s not dermal and vascular.

      • Vascular – moves water

Plant Organ Systems

While humans have 11 organ systems, plants only have two – roots and shoots.

• Shoot System

  • Includes leaves and stems and flowers

  • Food, minerals, & water are transported throughout the plant via shoot system.

  • The shoot system is everything ABOVE THE GROUND

• Root System

  • Rarely seen, but they are vital to a plant’s survival.

  • Only part of a plant that ABSORB water and nutrients from the soil

  • Not only essential in the means that it absorbs water and nutrients, it also anchors the plant, either in soil or onto another plant or object.

Organisms

Let’s backtrack a little bit and review organisms? What makes a living thing a living thing? Let’s review!

An organism is the highest level in the hierarchical organization of plants and animals. An organis is something that has or once had all the characteristics of life. Multicellular organisms usually have many organ systems. These systems work together to carry out all the jobs needed for the survival of the organism. Each organ system depends on the others and cannot work alone to kee the organism functioning.

• All organisms rely on their organ systems working together.

  • The cells in the muscle tissue of the stomach cannot survive without oxygen.

  • The stomach cannot get oxygen without working together with the respiratory and circulatory systems.

  • The respiratory system bring oxygen in the body.

  • The circulatory system delivers the oxygen to the cells in the organism.

• Like animals, plants have organ systems that work together to keep the organism alive.

  • The cells in the leaves & the stems of a plant need water to live, but they cannot absorb water directly.

  • Water diffuses into rutes and is transported through the stem to the leaves by the short, or transport, system.

  • Like animals, plants are a group of systems. They can only grow, reproduce, and survive if each part is carrying out its function. They need every cell, tissue, organ, and organ system to be a functioning organism.

Sexual and Asexual Reproduction

TYPES OF ASEXUAL REPRODUCTION

Each new organism is genetically identical to its parent. Learn more about different types below:

• Regeneration

  • Occurs when an offspring grows from a piece of its parent.

  • Examples include sea stars.

  • Think of it as regrowing from parts of a body.

• Budding

  • Orgamism grows on the body of the parent plant

  • Genetically identical

  • When the bud matures, it can break from the parent and live on its own.

  • However, in some cases, the bud remains attached to its parent. This starts to form a colony. An example of this is the hydra.

• Vegetative Reproduction

  • This can happen in many different ways, but in most cases, it involves structures such as the roots, stems, & leaves of plants.

  • Potatoes can sprout and grow into another plant that is genetically identical to the parent plant.

  • Raspberries, geraniums, strawberries, and peppermint can reproduce by sending out long horizontal stems called stolons or runners.

    • Whenever the stolon touches the ground, it can produce roots

    • When the stolon has grown roots, a new plant can grow – even if the stolons hav ebeen broken off from the parent plant.

Types of Sexual Reproduction

Each new organism is genetically different from the parents. Both plants and animals can do this. For both plants and animals, the sperm fertilizes an egg to form a zygote that grows into a new, unique organism.

• Plants

  • Plant sperm is usually pollen.

Take note of this diagram. This is likely to be tested over!

• Animals

Dissections & Anatomy

Anatomy of Eyes

Eyes are an amazing part of the body. They help you sense everything around you. So let’s delve deeper and explore parts of the human eye.

  The optic nerve is a white, round, pencil-thick bundle of nerves surrounded by a dark colored layer of muscle tissue at the back of the eye.

Parts of the Eye

1. Vitreous Humor 

• The fluid that helps the eye maintain shape.

• A transparent, colorless, gel-like substance located behind the lens in the chamber of the eye.

2. Ciliary Muscle

• This moves the iris.

• Th lens is held in place by a bunch of fibers which are attached to the ciliary muscles which change the shape of the lens to focus on something close buy (lens gets thicker) or something far away (lens gets thinner).

3. Iris

• The colorful part that opens & closes to let in light. The opening is called the pupil.

• The opening at the center of the iris is the pupil.

4. Lens

• The lens focuses light on the retina at the back of the eye.

5. Cornea

• A dome of clear tissue that allows light to enter and protects the front of the eye.

• It focuses light as it passes through.

6. Choloroid Layer

• Part of the middle layer of the eye wall, found between the sclerea and the retina. It contains blood vessels that deliver oxygen and nutrients to the inside parts of the eye.

7. Tapetum

• Also known as the lucidum

• A biological reflector system that provides the light-sensitive retinal cells with a 2nd opportunity for stimulation, thereby enhancing visual sensitivity at low light levels.

8. Retina

• Has 120 million rods to see in black, white, and shades of gray.

• Rods help you see in the dark

• Has 7 million cones to see in color.

• Cones are sensitive to red, green or blue. Working together, rods and cones let us see millions of colors.

9. Optic Nerve

• Bundle of nerve fibers that transmit visual signals/messages from the eye to the brain.

Here is a way to review the order in which the light passes through the eye:

Cute ⤜ Puppies ⤜ Love ⤜ Velvet ⤜ Rugs ⤜ Outside

Cornea ⤜ Pupil ⤜ Lens ⤜ Vitreous humor ⤜ Retina ⤜ Optic nerve

Frog Anatomy

Frog anatomy is quite similar to human anatomy.

We focused on the digestive system

Tongue is attached to the front

One major difference between frogs and humans is that frogs have a 3 chambered heart whereas humans have a 4 chambered heart; look more closely at in the circulatory system.

Important picture next slide