The Ear

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Parts of the Ear
Outer ear
The outer ear is called the pinna, which is the part outside the body and the ear canal. This part of the ear conducts sound waves into the ear. The complex folds, which form the outer ear not only, act as an amplifier, but also as a shield, to stop objects, such as insects, entering the ear.
Middle ear
Sound waves travel through the middle ear. On the outside edge of the middle ear is the eardrum. On the inside edge there is another drum which transmits the sound message to the brain along nerves. Between the two drums, there are three tiny bones, which help amplify the sound.
Inner ear
The inner ear is a delicate part of the ear, with fluid filled 'canals'. There is an inner ear on each side of the head, just next to the middle ear. They help the body with balance.
The snail like inner ear contains a maze of winding passages. This part of the ear deals with the reception and analysis of sound. It also keeps the body balanced.

The eye

Parts of the Eye


To understand more about how your eyes work, here is a brief description of the main structures of the eye and how they function:



Lens
The lens is a transparent body behind the iris, the coloured part of the eye. The lens bends light rays so that they form a clear image at the back of the eye – on the retina. As the lens is elastic, it can change shape, getting fatter to focus close objects and thinner for distant objects.

Cornea
The cornea is the transparent membrane which forms the outer coating at the front of the eyeball and covers the iris and pupil. It also focuses light on the retina.

Pupil
The pupil is the dark circular hole in the centre of the iris.

Iris
The iris is the coloured circle surrounding the pupil. It changes the size of the pupil and allows different amounts of light to enter the eye.

Retina
The retina is the light-sensitive inner lining of the back of the eye. Imagine that the eye is like a camera, and the retina is the film. Rays of light enter the eye and are focused on the retina by the cornea and lens. The retina produces an image which is sent along the optic nerve for the brain to interpret, rather like developing a camera film.

Macula
The macula is the small area at the centre of the retina responsible for what we see straight in front of us, at the centre of our field of vision. The macula is very important as it gives us the vision needed for detailed activities such as reading and writing, and the ability to appreciate colour.

Sclera
The sclera is the white of the eye and forms the outer coating of the eyeball.

Conjunctiva
The conjunctiva is a mucous membrane that covers the exposed front portion of the sclera and lines the inside of the eyelids.

Tear film
The tear film is the moist layer that covers and protects the outer surfaces at the front of the eye.

Vitreous
The vitreous is the clear, jelly-like substance that fills the inside of the eye from the lens to the retina.

The endocrine system ( El sistema endocrí)

What Is the Endocrine System?
The foundations of the endocrine system are the hormones and glands. As the body's chemical messengers, hormones (pronounced: hor-moanz) transfer information and instructions from one set of cells to another.

A gland is a group of cells that produces and secretes, or gives off, chemicals. A gland selects and removes materials from the blood, processes them, and secretes the finished chemical product for use somewhere in the body. Some types of glands release their secretions in specific areas. For instance, exocrine (pronounced: ek-suh-krin) glands, such as the sweat and salivary glands, release secretions in the skin or inside of the mouth. Endocrine glands,


The hypothalamus (pronounced: hi-po-tha-luh-mus), a collection of specialized cells that is located in the lower central part of the brain, is the primary link between the endocrine and nervous systems.

growth hormone, which stimulates the growth of bone and other body tissues and plays a role in the body's handling of nutrients and minerals
prolactin (pronounced: pro-lak-tin), which activates milk production in women who are breastfeeding
thyrotropin (pronounced: thigh-ruh-tro-pin), which stimulates the thyroid gland to produce thyroid hormones
corticotropin (pronounced: kor-tih-ko-tro-pin), which stimulates the adrenal gland to produce certain hormones


The thyroid (pronounced: thigh-royd), located in the front part of the lower neck, is shaped like a bowtie or butterfly and produces the thyroid hormones thyroxine (pronounced: thigh-rahk-seen) and triiodothyronine (pronounced: try-eye-uh-doe-thigh-ruh-neen). These hormones control the rate at which cells burn fuels from food to produce energy.






What Does the Endocrine System Do?
Once a hormone is secreted, it travels from the endocrine gland through the bloodstream to the cells designed to receive its message. These cells are called target cells. Along the way to the target cells, special proteins bind to some of the hormones. The special proteins act as carriers that control the amount of hormone that is available to interact with and affect the target cells. Also, the target cells have receptors that latch onto only specific hormones, and each hormone has its own receptor, so that each hormone will communicate only with specific target cells that possess receptors for that hormone. When the hormone reaches its target cell, it locks onto the cell's specific receptors and these hormone-receptor combinations transmit chemical instructions to the inner workings of the cell.

When hormone levels reach a certain normal or necessary amount, further secretion is controlled by important body mechanisms to maintain that level of hormone in the blood. This regulation of hormone secretion may involve the hormone itself or another substance in the blood related to the hormone. For example, if the thyroid gland has secreted adequate amounts of thyroid hormones into the blood, the pituitary gland senses the normal levels of thyroid hormone in the bloodstream and adjusts its release of thyrotropin, the pituitary hormone that stimulates the thyroid gland to produce thyroid hormones. Another example is parathyroid hormone, which increases the level of calcium in the blood. When the blood calcium level rises, the parathyroid glands sense the change and decrease their secretion of parathyroid hormone. This turnoff process is called a negative feedback system.

ovary

An ovary is an egg-producing reproductive organ found in female organisms. It is often found in pairs as part of the vertebrate female reproductive system. Ovaries in females are homologous to testes in males. The term gonads refers to the ovaries in females and testes in males.


En el estroma ovárico encontramos los folículos primordiales que madurarán, gran cantidad de vasos sanguíneos, tejido elástico y tejido conjuntivo laxo. El ovario, además de producir óvulos, segrega un grupo de hormonas, estrógeno y progesterona. Estas hormonas inducen y mantienen los cambios físicos de la pubertad y las características sexuales secundarias, apoyan la maduración del endometrio uterino a la espera de una posible implantación de un óvulo fecundado. Así mismo, suministran las señales adecuadas al hipotálamo y la pituitaria para mantener el ciclo menstrual. Los estrógenos tienen un papel preponderante en el mantenimiento de la grasa subcutánea, la fortaleza de los huesos y algunos aspectos de las funciones cerebrales.

thymus

In human anatomy, the thymus is an organ located in the upper anterior portion of the chest cavity just behind the sternum. Hormones produced by this organ stimulate the production of certain infection-fighting cells. It is of central importance in the maturation of T cells.

In the two thymic lobes, lymphocyte precursors from the bone-marrow become thymocytes, and subsequently mature into T cells. Once mature, T cells emigrate from the thymus and constitute the peripheral T cell repertoire responsible for directing many facets of the adaptive immune system. Loss of the thymus at an early age through genetic mutation or surgical removal results in severe immunodeficiency and a high susceptibility to infection.[4]

The stock of T-lymphocytes is built up in early life, so the function of the thymus is diminished in adults. It is, therefore, largely degenerated in elderly adults and is barely identifiable, consisting mostly of fatty tissue.[5]

However up to January 2001, it was thought that whilst the thymus gland is important to the immune system in the developing foetus, the gland becomes redundant after birth, and so can be surgically excised without harm to the patient.[6]

The ability of T cells to recognize foreign antigens is mediated by the T cell receptor. The T cell receptor undergoes genetic rearrangement during thymocyte maturation, resulting in each T cell bearing a unique T cell receptor, specific to a limited set of peptide:MHC combinations. The random nature of the genetic rearrangement results in a requirement of central tolerance mechanisms to remove or inactivate those T cells which bear a T cell receptor with the ability to recognise self-peptides.

testes

The testicles are each of the two male gonads, producing sperm, and sex hormones (testosterone). Bodies glandular that form the most important part of the male reproductive system. In some sporadic cases, the man presented only one testicle at birth.

adrenals

Endocrinology
The glands Adrenales
Anatomíade the adrenal glands:
The adrenal glands, also known as adrenal glands, are small triangular glands, located on top of both kidneys. Each adrenal gland consists of two parts, the region called external and internal adrenal cortex called adrenal medulla.



Role of the adrenal glands:
The adrenal glands work interactively with the hypothalamus and pituitary gland in the process:

The hypothalamus produces corticotropin releasing hormone, which stimulates the pituitary gland.
The pituitary gland, in turn, produces corticotrópicas hormones, which stimulate the adrenal glands to produce hormones corticosteroids.
Both sides of the adrenal glands - the adrenal cortex and medulla-performing distinct functions.

parathyroid

The parathyroid glands are small endocrine glands in the neck, usually located behind the thyroid gland, which produce parathyroid hormone. In rare cases the parathyroid glands are located within the thyroid glands. Most often there are four parathyroid glands, but some people have six or even eight

thyroid

The thyroid is one of the largest endocrine glands in the body. This gland is found in the neck inferior to (below) the mouth and at approximately the same level as the cricoid cartilage. The thyroid controls how quickly the body burns energy, makes proteins, and how sensitive the body should be to other hormones.

The thyroid participates in these processes by producing thyroid hormones, principally thyroxine (T4) and triiodothyronine (T3). These hormones regulate the rate of metabolism and affect the growth and rate of function of many other systems in the body. Iodine is an essential component of both T3 and T4. The thyroid also produces the hormone calcitonin, which plays a role in calcium homeostasis.

The thyroid is controlled by the hypothalamus and pituitary. The gland gets its name from the Greek word for "shield", after its shape, a double-lobed structure. Hyperthyroidism (overactive thyroid) and hypothyroidism (underactive thyroid) are the most common problems of the thyroid gland. Specialists are called thyroidologists.

pituitary

The pituitary gland, or hypophysis, is an endocrine gland about the size of a pea that sits in a small, bony cavity (sella turcica) covered by a dural fold (diaphragma sellae) at the base of the brain. The pituitary fossa, in which the pituitary gland sits, is situated in the sphenoid bone in the middle cranial fossa at the base of the brain.

The pituitary gland secretes hormones regulating homeostasis, including trophic hormones that stimulate other endocrine glands. It is functionally connected to the hypothalamus by the median eminence.

cerebellum - tema 4

One of the most impressive parts of the human brain, named the cerebellum, has been underestimated for centuries. Located at the lower back of the brain, it is a fist-sized structure whose function is now being reappraised. Formerly this structure was thought to have only a motor function, which it performed by helping other motor regions of the brain to do their work effectively. But during the past decade a broader view of its function has emerged as a result of new research, and now the cerebellum is regarded as a structure that can help not only motor but also nonmotor regions to do their work effectively. In fact, the cerebellum has been compared to a powerful computer, capable of making contributions both to the motor dexterity and to the mental dexterity of humans, both of which are required for the emergence of fluent human language.

pons - tem 4

thalamus - tema 4

Function:


Motor Control

Receives Auditory, Somatosensory and Visual Sensory Signals

Relays Sensory Signals to the Cerebral Cortex
Location:


The thalamus is a large, dual lobed mass of grey matter cells located at the top of the brainstem, superior to the hypothalamus.
Images:


View fascinating images of the

amygdala

1. An almond-shaped neuro structure involved in producing and responding to nonverbal signs of anger, avoidance, defensiveness, and fear. 2. A small mass of gray matter that inspires aversive cues, such as the freeze reaction, sweaty palms, and the tense-mouth display. 3. A primeval arousal center, originating in early fishes, which is central to the expression of negative emotions in man.

hyppocampus - tema 4

cerebral cortex - tema 4

THE CIRCULATION

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1. THE CIRCULATION

The circulatory system is the responsable to port the blood to all of the body.Is made up for the heart and blood vessels. The funcion of heart boost the blood to the blood vessels.

The blood

The blood is a liquid red, on circule in the interior of blood vessels when recorr all the organism. The our body have aproximally five liters of blood.Some of this functions are transport substances to all organism and protect the body of malalties

The composition of blood:

The blood is made up for a liquid appointed plasm and cells of blood when sure in the plasm.

The plasm is a liquid yellow formed basically of water. Transport nutritives substances and residuals substances
The blood cells are:

The red blood cells have form of cd and are red. Transport oxygen and carbon dioxe.

Whyte blood cells. Have irregular form and semi transparents. They combat the infeccions made up the organisms how influenza.

THE DIGESTION



This is the proces of digestion

THE PARTS OF DIGESTION

How digest food?

Digestion includes the mixture of food, its passage through the digestive tract and chemical decomposition of large molecules into smaller molecules. It begins in the mouth, where masticamos and eat, and ends in the small intestine. The chemical process varies slightly depending on the type of food.

The large and hollow organs of the digestive system have muscles that allow its walls move.
The first major movement occurs when muscle eat foods or liquids. Although this part of the process is voluntary, begins as soon as it becomes involuntary happens to be under the control of nervios.Despues, passes through the intestines (first by the great and then by paqueño) and within a few hours be accepted

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1.1 THE TISSUES




















TISSUES: A tissue is a mass of cells each of which performs a similar function. The four types of tissue are epithelial, connective, muscular, and nervous.



ORGANS:An organ is a structure composed of two or more tissues which combine to perform a specific function(s). Examples of organs are the stomach, heart, lungs, skin, etc.




AN ORGAN SISTEM:An organ system is composed of two or more organs which combine to perform a specific function(s). Examples of organs systems are the cardiovascular system, muscular system, skeletal system, nervous system, et







TISSUES IN ANIMALS : TYPES OF TISSUES

Epithelial : Epithelial tissues are widespread throughout the body. They form the covering of all body surfaces, line body cavities and hollow organs, and are the major tissue in glands. They perform a variety of functions that include protection, secretion, absorption, excretion, filtration, diffusion, and sensory reception.

CONNECTIVE TISSUES: Connective tissues bind structures together, form a framework and support for organs and the body as a whole, store fat, transport substances, protect against disease, and help repair tissue damage.

MUSCLE TISSUES:Muscle tissue is composed of cells that have the special ability to shorten or contract in order to produce movement of the body parts. The tissue is highly cellular and is well supplied with blood vessels.

NERVOUS TISSUES:
Nervous tissue is found in the brain, spinal cord, and nerves. It is responsible for coordinating and controlling many body activities. It stimulates muscle contraction, creates an awareness of the environment, and plays a major role in emotions, memory, and reasoning. To do all these things, cells in nervous tissue need to be able to communicate with each other by way of electrical nerve impulses.

2. THE ANIMAL CELL

3.THE HUMAN SISTEMS