The Skeleton and muscles

The Skeleton and muscles

By Naomi Keddy

The Muscles and skeleton working together to form the musculoskeletal system.

The Function the musculoskeletal system:

 The skeleton provides:

•    Support.
•      Protection of internal organs.
•     Rigid frame for movement.
•      Shape
•      Blood cell manufacture

The human contains 206 bones and it is divided into two parts which are the axial and appendicular skeleton.

The Axial skeleton is made up of the:

•       Skull,
•     Ribs (12 pairs),
•  Sternum (breastbone)

The appendicular skeleton contains the:

•   Pectoral girdle
•    Attached limb (arm)
•      Pelvic girdle
• Attached limb (leg)

  A Vertebrae is an animal with a backbone. The spine is a series of 33 bones (vertebrae).

There are Five Types of Vertebrae:

•   Cervical Vertebra: There are seven of these. The atlas is the first vertebra and supports the skull.
•     Thoracic Vertebra: There are twelve of these that articulate or connect with a pair of ribs.
•  Lumber Vertebra: There are five of these. They have a thick centrum for support and elongated diagonal methods for the attachment of abdominal muscles.
• Sacral Vertebra: There are five of these that are fused to form the sacrum which forms part of the pelvic girdle.
• Coccyx Vertebra: There are four of these that are fused to form the coccyx (tail).

Vertebrae are separated by discs of cartilage.

The twelve ribs are arranged as:

•   The first seven ribs connect with the sternum and are called true ribs.
• The next three ribs connect with the seventh rib and are called false ribs.
•  The last two ribs do not connect at the front and are called floating ribs.

The Composition of Bone:

 The shaft of the bone is called the diaphysis and the head of the bone is called the epiphysis.

Cartilage covers the end of the femur. It protects the ends of bones and allows friction free movement. Cartilage is made of a fibrous protein called collagen. Cartilage has no blood vessels or nerves.

 Types of bones:

• Compact bone is solid bone and is made of bone cells called osteoblasts in a matrix of salts and protein. This gives the bone strength and the protein gives the bone flexibility. Compact bone is found in the diaphysis of the bone.
•   Spongy bone is like compact bone but more porous it is hollow with bone marrow. Spongy bone is found in the epiphyses of the bone

•  Bone marrow is a soft material found in the medullary cavity of the diaphysis.

-Red bone marrow is where blood cells are produced

 -yellow marrow which is inactive and rich in fat.

The Growth of Bone:

• Osteoblasts are bone forming cells that produce the protein collagen. 
•  Growth plates made of cartilage are found between the epiphysis and diaphysis of a bone. Here, cartilage is formed and turned into bone.
• Osteoclasts are large cells that digest bone that lines the medullary cavity.

Arthritis

Cause:

There are many different types of arthritis:

•  Osteoarthritis is the most common, occurring in older people due to the wearing down of cartilage at synovial joints. The underlying bones become large and the joint swells and becomes stiff and sore.
•   Rheumatoid arthritis is an auto-immune disease.

Prevention:

·         Reduce damage to joints,.

Treatment:

•    Anti-inflammatory medication.
•  Rest.
• Weight loss.
•    Replacement of joint by surgery. 

Joints is where bone meet.

Joints

1. Immovable joints:  (Fixed or fused) joints such as the skull.

2. Slightly movable joints: joints such as those between vertebrae

3. Freely movable or synovial joints are joints such as:

·         Hinge Joints – E.g. elbow and knee. They allow movement in one direction only.

·         Ball and Socket Joints – E.g. shoulder and hip. These allow movement in all directions. 

Ligaments join bone to bone.

Tendons join muscle to bone.

There are Three Types of Muscles:

1. Skeletal Muscle: . It is also called striped muscle.. It is also called voluntary muscle.

2. Smooth Muscle: unstriped Muscle. It is also called involuntary muscle.

3. Cardiac Muscle: This is found in the heart. Cardiac muscle is involuntary. Cardiac muscle does not get tired 

An Antagonistic Pair: is two muscles that produce opposite effects.

• The biceps contracts to raise the forearm. it is a flexor.
• The triceps contracts to straighten the forearm. it is an extensor.

The Senses

The Senses

By Naomi Keddy

The human body contains five known senses which are taste, touch, smell, hearing and sight.

Taste:

The tongue is the organ of taste. The taste buds taste the following:

• sweet
• Sour
• Salt
• Bitter

The nose is the organ of smell. Olfactory neurons in the nose detect many smells.

The Eye:

The Eye is the organ of sight and it maintains many parts of the eye and functions are as follows:

Eyelids: can cover and protect the eyes. 

Conjunctiva: thin transparent lining protecting the cornea

Cornea: front transparent part of the sclera. It focuses light rays on the retina.

Sclera: is a though, white coat that holds the eye in place.

Choroid: contains blood vessels supplying food and oxygen to the cells of the eye. 

Retina: the innermost layer that contains the receptor cells (rods and cone shape).

The fovea: is where our best vision is (mainly cone shape)

Iris: contains blood vessels and melanin [giving us our eye colour], and controls the amount of light entering the eye 

Pupil: is the black circle at the front of the eye. It lets light into the eye.

Cillary muscles: change the shape of the lens to focus the light on the retina.

Aqueous and vitreous humours: keeps the eye in shape.

Optic nerve: carries impulses to the brain.

Lens: focuses light on retina.

The Ear:

The Ear is the organ of hearing and balance. The functions of the parts of the ear are as follows:

• Pinna: outer visible ear, funnels sound into the ear canal
• Auditory canal: tube leading to the ear drum. It has hairs and wax glands to trap dirt and germs
• Eardrum: membrane of skin that vibrates when sound waves hit it and carries vibrations to the middle ear
• Ossicles: (the hammer, anvil, stirrup) amplify the vibrations and pass them on the cochlea.
• Cochlea: is responsible for hearing. It contains nerves that convert sound vibrations into electrical impulses.
• Semi-circular canals: help us keep our balance and posture.
• Eustachian tube: is not part of the ear, it connects the middle ear the pharynx and equalises pressure.
• Organ of corti: in the cochlea which contains receptor cells that allow hearing.

Hearing disorder:

Glue Ear is:

• A hearing disorder
• Caused by too much sticky fluid in middle ear
• Corrected by decongestants and grommets.

Excretion

Excretion

By Naomi Keddy

Homeostasis: is the maintenance of a constant external environment in an organism. Excretion helps homeostasis Example of excretion helping homeostasis is temperature regulation in animals. The control of temperature in the body is needed because temperature regulates the chemical reactions.

Ectotherms: gain or lose heat to their external environment.

Endotherms: generate their own heat from metabolic reactions.

Function of the skin:

Protection:

• Epidermis protects against damage.

• Melanin protects against ultraviolet radiations.

• Sebum helps keep the epidermis intact.

• Vitamin D is made in the skin

• Fats are store in the skin for heat and energy.

• Skin is used as sense organ for touch, pain or temperature

• Excretion sweat removes water and salt from the body.

Temperature regulation:

• Cold conditions cause:

1. Hairs to stand up to keep the skin warm.

2. Blood vessels become narrow to retain heat.

3. Shivering is movement to keep the body warm.

• Warm conditions cause:

1. Sweating, which cools the body due evaporating.

2. Blood vessels widen to lose heat.

 The role of the excretory system:

• Regulating body temperature.

• Controlling osmosis

• Controlling the concentration of body fluids

• Removing waste products.

Organs of Excretion:

• Lungs: excrete water and carbon dioxide.

• Skin: excrete water and salt.

• Kidneys: excrete water, salt and urea in the form of urine.

The Human excretory system:

The Kidneys:

The urinary system consists of two kidneys, two ureters, the bladder and the urethra.

The Kidneys are located just below the diaphragm.

The mains processes of the kidneys:

• Filtration: The incoming of the blood into the kidneys is filtered. This takes place in the outer cortex.

• Reabsorption: Some useful materials are taken back into the blood and this is called reabsorption. It occurs in the cortex and the medulla.

• Secretion: Some substances are secreted from the blood into the cortex such as potassium and hydrogen ions. 

The Functions of the kidneys:

1. Excretion: The kidneys remove waste products from the bloodstream and convert them to urine.
2. Water content: The kidneys control the water content by varying the water content of urine.
3. Salt concentration: The kidneys control the salt concentration of body fluids by varying the amount of salt released in the urine.
4. pH Control: The kidneys control the pH of the body fluids by producing urine that is either more or less acidic. 

The Nephron:

 The nephron carries out the function of the kidneys and it is located in the cortex and the medulla of the kidneys.

The processes of the nephron:

• Filtration means that water and small molecules pass from the blood to the nephron.

1. Blood entering the nephron in the afferent arteriole contains waster products.

2. Filtration takes place in the glomerulus. Small molecules such as glucose, amino acids, vitamins and minerals are forced out of the plasma into bowman’s capsule. 

• Reabsorption means that molecules pass from the nephron back into the blood. 

1. Most of the water is reabsorded by osmosis. Useful molecules such as glucose, amino acids and vitamins are reabsorbed by diffusion and active transport ( means it requires energy in the form of ATP)

2. The descending limb of the loop of Henle is permeable to water so small amount of water is reabsorbed by osmosis.

3. The ascending limp of the loop of Henle is permeable to salts. 

The hormone ADH:

• Is released from the pituitary gland.

• Controls the volume of urine formed.

• Is released when plasma has too little water or too much salt.

ADH Causes:

• Increased reabsorption of water in the distal tubule and the collecting ducts.

• A low volume of urine.

• ADH is not released when we drink sufficient water or consume a low salt diet.

A Mysterious Discovery: New Born Baby girl pregnant with Twins

I thought this to be an interesting discovery and thought any biology lovers would too, so I wrote my own  article on it based on my sources.
A new born baby girl in China was born and was found to be pregnant with twins in her abdomen. The Medical Journal has reported.  Scan were taken and in them scans a great amount of mass was found in the baby's abdomen, the doctors assumed it could have been a tumour. New scans revealed the mass was in fact made up of two separate cell structures.
The unborn twins, 8 to 10 weeks gestated, had legs, arms, complete with spines, well-developed rib cages, intestines and embryonic brain tissue. The twins were successful removed from the baby. It is still unknown to what might of have caused this, but there are over 200 cases where are foetus is born in a new born baby.

Source: Tahir, T. and Metro (2015) Baby girl born ‘pregnant’ with twins. Available at: http://metro.co.uk/2015/02/07/baby-girl-born-pregnant-with-twins-5053526/ (Accessed: 2 November 2015).

Photosynthesis

By Naomi Keddy

Photosynthesis is the production glucose in plants with sunlight, carbon dioxide and water and they can do this because they contain the green pigment called chlorophyll which able to absorb all the required things for this process.

Role of photosynthesis:
-Plants use it to make their own food
-Animals get their food from plants
-Plants produce oxygen which is needed for most living things
-Photosynthesis was responsible for forming fossil fuels
Photosynthesis is divided into two stages, which are light stage and dark stage.
Light stage:
1. Light is absorbed
2. Water is split
3. The products of the splitting of water

Light: 
Light is absorbed by the sun. The light is trapped by the pigment chlorophyll. Chlorophyll is found in the organelle called chloroplasts. Only green plants contain chlorophyll pigments. Sunlight that is absorbed by the plant provides energy to the plant.


Water:
Some of the trapped sunlight provides energy and some of that energy is used to split water into four protons (4H+), four electrons (4e-) and Oxygen (02)


Products:
The three products from the splitting of water go to:
-The electrons are passed to the chlorophyll
-Protons are released into a storage pool in the chloroplast
-Oxygen is passed into the chloroplast into the cytoplasm and then into the atmosphere. 

Light stage is divided into two pathways: 
-Pathway 1-Cyclic electron flow
-Pathway 2-noncyclic electron flow

Pathway 1-Cyclic electron flow:
The light stage occurs in the grana of the chloroplast
-The high-energised electrons pass from the reaction centre chlorophyll to an electron acceptor.
-They pass from the electron acceptor to a series of other electron acceptors and back to the chlorophyll.
-when the electrons return to the chlorophyll they lose energy.
-The energy they release is trapped by ADP and a phosphate to form ATP

Pathway 2-non-cyclic electron flow:
-Two high energised electrons leave the chlorophyll.
-They pass to an electron acceptor and along another series of electron acceptors
-This time the energised electrons do not return to the chlorophyll.
-They lose some energy.
-The energy released is used to form more ATP
-The electrons lost from chlorophyll 1 molecule are picked up by the NADP+ and combine with protons from the proton pool to form NADPH.

𝑵𝑨𝑫𝑷+ + 𝟐𝒆_ + 𝑯+ −→𝑵𝑨𝑫𝑷𝑯

-This NADPH is used in the dark stage

-The chlorophyll is now short of electrons. It gains new electrons from the splitting of water.

-This NADPH is used in the dark stage
-The chlorophyll is now short of electrons. It gains new electrons from the splitting of water.

Dark stage:

-The dark stage takes place in the stroma of the chloroplast.

-The dark stage is controlled by enzymes. 

-This means it is affected by temperature. 

-Carbon dioxide from the atmosphere or from respiration enters the chloroplast.

-The hydrogen ions are released from NADPH to convert carbon dioxide into Glucose.

. The energy for this process comes from the breakdown of ATP that was formed in the light stage.

-NADP+ and ATP are recycled back into the light stage

Light stage: 

-Occurs in the Grana of the cell

-Requires Light

-ATP is produced

-Oxygen is produced

-NADPH is produced

Dark Stage:

-Occurs in the stroma

-Doesn’t require light

-ATP is used

-NADPH is used

-Carbon dioxide is converted into glucose

The Cell Structure

The Cell structure

By Naomi Keddy

The Microscope:

-Coarse focus: For Approx. focusing.

-Fine Focus: For Precise focusing.

-Eye Piece: Magnifies the image.

-Nosepiece: Rotates to move to desire lens.

-Objective Lens: Magnifies the image.

-Stage: Supports the slide.

-Mirror: To supply light to the slide.

 Animal and plant cell structure:

Animal cell:

-Protoplasm: Is all the living parts of a cell.

-Cytoplasm: Is all the living material in the cell outside the nucleus.

-Ribosomes: To make protein.

-Cell membrane: To retain the cell contents

-Nucleus: Contains the strand of DNA. The Nucleus is the control of the cell.

-Mitochondrion: Is the sites of respiration.

-Chromatin: Is the name given to chromosomes when they are elongated and dividing

Mitochondria: Are the sites of respiration and it supplies energy to the cell.

Plant Cell:

-Cell Wall: To support and strengthen the cell.

-Chloroplast: Contain the green pigment that allows plants carry out photosynthesis.

-Vacuoles: contain a fluid called cell sap, this is a solution of salts, sugar and pigments

Chlororplasts: are surrounded by double membranes. They have membranes stacks which contain the green pigment chorophyll. They also have a loop of DNA.

The differences between plant and animal cells:

-Plants have a cell wall and animal do not have a cell wall.

-Plants have a chloroplasts and animal cell do not have chloroplasts.

-Plants have large vacuoles and animal do not have large vacuoles.

The Cell Membrane or Plasma Membrane:

All living membranes have the identical structure. They are composed of phospholipids and proteins. Cell membranes are thin. The phospholipids are arranged in a double layer called the lipid bilayer. The proteins are entirely or partly fixed in the bilayer and are able of movement. Phospholipids have a water loving phosphate group and a water-hating lipid group. The phosphates are on the outer surfaces and the lipids are in the middle.

Functions of membranes:

-Retain the cell contents.

-Recognise molecules that touch them.

-Control what enter or leaves the cell.

-Give support to the cell.

Prokaryotic and Eukaryotic cells:

Prokaryotic cells: do not have a nucleus or membranes-enclosed organelles.

Prokaryotic cells:

-Are singled cell

-Have a circular loop of DNA

-Have small cells

-Do not have membranes-enclosed organelles such as mitochondrion and chloroplast.

-Include bacteria

Eukaryotic Cells: Have a nucleus and cell organelles, all of which are enclosed by membranes.

Eukaryotic cells:

-Have a nucleus

-May have membrane-enclosed organelles such mitochondrion and chloroplasts

-Have large cells

-Include animals, plant and fungi