Anatomy and Physiology Notes

Anatomy and Physiology

Introduction to Anatomy and Physiology

• Anatomy and physiology are fundamental areas of study in the life sciences.
• Anatomy studies the body's internal and external structures and their physical relationships.
• Physiology is the study of the functions of these structures.
• Both terms are derived from Ancient Greek: anatomy (study of organism structure) and physiology (study of regular mechanisms within living systems).
• Anatomy and physiology involve the scientific study of the body's structure and functions.
• A single organism is composed of billions/trillions of cells, tissues, and organs, involving both microscopic and macroscopic structures.
• Cells are microscopic and examined under electron microscopy, while organs and organ systems are macroscopic and visible to the naked eye.

Anatomy

• Anatomy is a branch of natural science and biology.
• Includes human, animal, and plant anatomy.
• Human anatomy was the first to be studied for examining internal structures and injuries.

Branches of Anatomy

• Macroscopic (Gross) Anatomy
• Microscopic Anatomy
• Developmental Anatomy

Macroscopic Anatomy

• Deals with large body parts visible to the naked eye.
• Examples: Anatomy of the kidney, heart, lungs, etc.

Types of Macroscopic Anatomy

• Regional Anatomy
• Systemic Anatomy
• Surface Anatomy

Regional Anatomy

• Study of different structures in a particular region.

Systemic Anatomy

• Study of human structures system by system.

Surface Anatomy

• Study of only internal structures of a human body.

Microscopic Anatomy

• Deals with minute structures examined through a microscope.
• Example: Different types of cells.

Classification of Microscopic Anatomy

• Cytology: Study of human blood cells.
• Histology: Study of different tissues in the human body.

Developmental Anatomy

• Study of structural changes in the body throughout the lifespan.
• Embryology: Used to understand the development process before childbirth.

Physiology

• Physiology is a branch of natural science and biology focused on the complete functioning system of a body.

Types of Physiology

• System Physiology
• Comparative Physiology
• Medical Physiology

System Physiology

• Study of the complete functioning of body systems.

Comparative Physiology

• Study of various characteristics of living organisms.

Medical Physiology

• Study of physiological dysfunctions and diseases related to human body systems.
• Living systems can be defined from broad to minute perspectives.
• Each perspective provides information about how or why a living system functions.

Human Physiology

1. Studies the functions of the human body, including organ systems and their interactions.
2. Compares physiological mechanisms across different species to understand evolution and similarities.
3. Focuses on the functions of cells, examining processes like metabolism and communication.
4. Explores how different organ systems work together to maintain homeostasis and overall function.
5. Investigates physiological responses and adaptations to physical activity and exercise.
6. Examines how organisms adapt to and function in various environments.
7. Studies physiological changes associated with diseases and disorders.
8. Focuses on the endocrine system and the role of hormones in regulating physiological processes.
9. Studies the nervous system, including signal transmission and bodily function regulation.
10. Examines the heart, blood vessels, and blood, studying blood circulation and pressure regulation.
11. Investigates functions of the respiratory system, including ventilation and gas exchange.
12. Deals with kidney and urinary system functions, including blood filtration and electrolyte balance.
13. Focuses on male and female reproductive systems, studying gametogenesis and hormonal regulation.
14. Studies physiological processes in plants, such as photosynthesis and nutrient transport.

• At the chemical level, atoms, molecules, and chemical bonds create the foundation for living activity.
• The cell is the smallest unit of life.
• Organelles within the cell are specialized bodies performing specific cellular functions.
• A tissue is a group of similar cells performing a common function (e.g., muscle tissue).

Cells, Tissues, Organs, and Systems

• If the human body is broken apart, the cell is the most basic unit.
• The average adult has 30-40 trillion cells, with approximately 242 billion new cells produced daily.
• A tissue is a group of cells with similar functions that come together.
• Tissues form organs, organs form organ systems, and organ systems form a complete organism.

The Skeleton and Muscles

• The human body exhibits various movements enabled by the skeleton.
• Humans have as many as 300 bones at birth, which fuse to 206 in adulthood.
• Muscles are specialized tissues that assist bones in locomotion.
• Muscles attach to bones via tendons.
• Limb movement results from muscle contraction and relaxation.
• Joints provide flexibility, but muscles must act on bones to enable bending or stretching.
• The skeleton protects vital organs, including the heart, lungs, and liver.
• Bones are connected by ligaments, a fibrous connective tissue.

Human Body Structure

• Human body parts include a head, neck, and four limbs connected to a torso.
• The skeleton, composed of cartilage and bone, gives the body its shape.
• Internal parts like the lungs, heart, and brain are enclosed within the skeletal system and housed within internal body cavities.
• The spinal cord connects the brain with the rest of the body.
• Humans have a unique ability to use their hands for tasks requiring dexterity.

Human Body Cavities

• Cranial cavity: Protects the brain and central nervous system.
• Pleural cavity: Protects the lungs.
• Abdominal cavity: Houses the intestines, liver, and spleen.
• Humans have evolved separately but share a common ancestor, resulting in a similar body plan to other organisms.
• Giraffes have the same number of vertebrae in their neck as humans (seven).

Human Physiology

• Human physiology refers to the physical, mechanical, and biochemical functions of humans.
• It connects health, medicine, and science by studying how the body adapts to physical activity, stress, and diseases.
• The list of human body parts varies due to ongoing debate about the definition of an organ; there are approximately 79 identified organs.
• Vestigial organs have lost their function during evolution.
• Organ systems are specialized to perform specific functions.
• Five crucial organs for survival are the brain, heart, liver, lungs, and kidneys.
• Claude Bernard is considered the father of physiology.

The Human Ear

• The ears are paired organs on each side of the head that aid in hearing and balance.
• Conditions affecting the ears include infection, tinnitus, and Meniere's disease.
• Proper ear care helps maintain ear health.
• The primary functions of the ear are hearing and balance.

Hearing

• Sound waves enter the ear canal, causing the tympanic membrane (eardrum) to vibrate.
• The vibration is passed to three ossicles (tiny bones) in the middle ear.
• The ossicles amplify and transmit the sound waves to the inner ear.
• In the inner ear, stereocilia (hair cells) transform vibrations into electrical energy and send it to the brain via nerve fibers.

Balance

• The inner ear contains semicircular canals filled with fluid and hair-like sensors.
• Head movement causes fluid to move the hairs.
• Hairs transmit information to the brain via the vestibular nerve.
• The brain sends signals to muscles to maintain balance.
• The ear is divided into three anatomical regions:
  • Outer ear
  • Middle ear
  • Inner ear

Outer Ear

• Visible part of the ear, also called the auricle or pinna.
• Consists of ridged cartilage, skin, and glands that secrete earwax.
• The funnel-shaped canal leads to the eardrum (tympanic membrane).

Auricle

• Also known as the pinna, a wrinkly musculocutaneous tissue attached to the skull that captures sound.
• Made of cartilage covered with skin.
• Medial (inner) and lateral (outer) aspects.
• The medial aspect is attached to the skull and has no major practical significance.
• The middle ear contains Auditory Ossicles

Auditory Ossicles

• Three smallest bones in the human body: Malleus, Incus, and Stapes.

• Transmit sounds to the internal ear, specifically to the labyrinth.

• Articulate with synovial joints and are moved by middle ear muscles to transmit vibrations.

• Malleus (hammer)

• Incus (anvil)

• Stapes (stirrup)

External Acoustic Meatus

• Bony-cartilaginous canal from the auricle to the middle ear, separated by the tympanic membrane (eardrum).
• Consists of lateral cartilaginous part and medial bony part.
• The tympanic cavity is a bony-membranous cavity.

Tympanic Cavity

• Bony-membranous cavity shaped like a biconcave lens or six-sided prism.
• Auditory ossicles are located within.

Malleus

• Laterally attached to the tympanic membrane, medially articulates with the incus via the incudomalleolar joint.
• Receives and transmits sound vibrations.
• Parts: head, neck, anterior and lateral processes, and handle.

Incus

• Anatomical connection between the malleus and stapes.
• Parts: body, long limb, and short limb.
• The body is located in the epitympanic recess and articulates with the head of the malleus via the incudomalleolar joint.
• The long limb is parallel to the handle of the malleus and projects the lenticular process, which articulates with the stapes via the incudostapedial joint.
• The short limb extends posteriorly and attaches to the posterior wall of the tympanic cavity through the posterior ligament of the incus.

Inner Ear

• The most complex part of the ear, also called the labyrinth.
• Located in the petrous part of the temporal bone, made up of bony cavities fitting specific membranous parts.

Vestibule

• A central bony cavity containing the utricle and saccule of the vestibular labyrinth.
• Communicates with the tympanic membrane through the oval window, the cochlea anteriorly, and the semicircular canals postero-superiorly.

Semicircular Canals

• Positioned postero-superiorly to the vestibule.
• Each canal makes a 90-degree angle with the others.
• Contain the semicircular ducts of the membranous labyrinth.

Cochlea

• Greek for snail, a spiral and hollow bone chamber where sound waves propagate from the base to the apex.
• A tube called the spiral canal of the cochlea twists around a central bony column (modiolus) 2.5 times.
• Contains the osseous spiral lamina attached to the outer wall of the modiolus, extending into the cochlear canal.

The Human Eye

• The eye is a complex sensory organ that enables visualization of objects, light perception, color, and depth perception.
• Similar to cameras in function.
• Understanding its structure and working helps in understanding how a camera functions.
• The eye consists of six muscles: medial rectus, lateral rectus, superior rectus, inferior rectus, inferior oblique, and superior oblique.
• These muscles control eye movement by providing different tensions and torques.
• The eye is shaped like a slightly compressed ball, about 1 inch in diameter in adults.

Parts of the Eye

• Seven main parts: Sclera, Cornea, Iris, Pupils, Lens, Retina, and Optic nerves.

Sclera

• The outer, tough, white protective layer.

Cornea

• The transparent front part of the sclera through which light enters.
• Made of water and collagen.
• Protected and lubricated by tears.

Iris

• Dark muscular tissue and ring-like structure behind the cornea that determines eye color.
• Adjusts exposure by controlling the size of the pupil

Pupil

• Small opening in the iris that controls the amount of light entering the eye.

Lens

• Transparent structure behind the pupil that focuses light on the retina by changing shape via ciliary muscles.
• Thinner for distant objects, thicker for nearby objects.

Retina

• Light-sensitive layer composed of nerve cells that convert images into electrical impulses.
• Transmits electrical impulses to the brain through optic nerves.

Optic Nerves

• Consist of cones and rods.
• Cones are more sensitive to bright light and are used for detailed central and color vision.
• Rods are more sensitive to dim lights and are used for peripheral vision.

How the Eyes Work

• The parts of the eye work together to help you see images and send visual information to your brain.

1. Light enters through the cornea and goes to the lens.
2. The pupil gets bigger and smaller to control the amount of light.
3. The cornea and lens refract (bend) the light to bring what you’re seeing into focus.
4. Light reaches the retina and is changed into electrical impulses or signals.
5. The optic nerve transfers these signals to the visual cortex in the brain.
6. The brain interprets what you’ve seen and combines visual information from both eyes into one clear image.

• Refraction is the change in direction of light rays as they pass between different mediums.

The Endocrine System

• The endocrine system consists of organs called glands that create and release hormones.
• Hormones are chemicals that coordinate bodily functions by carrying messages to organs, skin, muscles, and tissues.
• The system is made up of glands that produce and release different hormones targeting specific things in the body.
• Glands are located throughout the body, including in the neck, brain, and reproductive organs.
• Sizes vary; the largest gland is the pancreas (about 6 inches long).

Major Endocrine Glands

• Pituitary Gland
• Thyroid Gland
• Parathyroid Glands
• Adrenal Glands
• Pineal Gland
• Pancreas

Pituitary Gland

• Enclosed deep within the skull, about the size of a pea.
• Hangs on a stalk at the base of the brain.
• Consists of an anterior portion that produces hormones and a posterior portion with neural links.
• Considered the master gland as it controls other glands in the endocrine System.

Thyroid Gland

• Located at the front of the neck, low in the throat between the windpipe.
• Brownish red in color with blood vessels.
• Secretes thyroid hormones, mainly T3 and T4, which influence metabolism.

Parathyroid Glands

• Four small glands located behind the thyroids in the neck.
• Influence calcium levels by producing parathyroid hormone.
• Excess production can cause brittle bones and kidney stones.

Adrenal Glands

• Sit atop the kidneys and are no larger than a walnut.
• Produce over 150 hormones regulating bodily functions.
• Adrenaline triggers the flight or fight response by:
  • Increasing blood sugar levels
  • Increasing blood supply to muscles
  • Dilating the pupils
  • Increasing the heart rate
  • Tightening the jaw muscles

Pineal Gland

• Located between the two halves of the brain, also known as the “third eye.”
• Produces melatonin, influencing the body's internal clock, or Circadian Rhythm.
• Affects the sleep/wake cycle; noticeable effects emerge when sleep-deprived.

Pancreas

• Both exocrine and endocrine gland behind the stomach.
• Approximately 6 inches long and flat.
• Roles include producing digestive enzymes and hormones like insulin and glucagon.
• Insulin: Produced by β cells, regulates blood glucose levels.
• Glucagon: Produced by α cells, prevents glucose levels from dropping too low.

Endocrine System Function

• The endocrine system continuously monitors hormone levels in the blood.
• Hormones deliver messages by locking into the cells they target.
• The pituitary gland senses hormone level changes and directs other glands to adjust production accordingly.
• This process, called homeostasis, functions like a thermostat.

Endocrine System Disorders

• Hormone imbalance can lead to diseases.
  • Too much or too little hormone is harmful.

Goitre

• Excess thyroid hormone symptoms:
  • Excess sweating
  • Weight loss, etc.
• Enlargement of the thyroid gland due to:
  • Iodine deficiency
  • Hyperthyroidism
  • Hypothyroidism

Graves’ Disease

• Exophthalmic goiter.
• A type of hyperthyroidism.
• Overactive thyroid gland secretes too much thyroid hormone.

Diabetes Mellitus

• The pancreas produces glucagon and insulin to balance blood glucose levels.
• Diabetes mellitus is a common condition.

Hormone Effects

• Hormones affect nearly every bodily process, including:
  • Metabolism
  • Growth and development
  • Emotions and mood
  • Fertility and sexual function
  • Sleep
  • Blood pressure
• Imbalances can cause health problems such as weight gain and mood changes.
• Illness, stress, and medications can cause hormone imbalances.
• Endocrine disrupters (chemicals in pesticides, plastics, and cosmetics) can also affect the endocrine system by changing hormones messages

The Digestive System

• The digestive system is a network of organs that help you digest and absorb nutrients from food.
  • Gastrointestinal (GI) tract
  • Biliary system
• The GI tract is a series of connected hollow organs from the mouth to the anus.
• The biliary system is a network of three organs that deliver bile and enzymes to the GI tract.

Parts of the Digestive System

• Mouth
• Pharynx
• Oesophagus
• Stomach
• Small Intestine
• Large Intestine
• Rectum
• Accessory Organs (Pancreas, Liver, Gallbladder)

Mouth

• Food's entry point; contains teeth, salivary glands, and tongue.
• Teeth grind food into smaller pieces, moistened with saliva before the tongue pushes food into the pharynx.

Pharynx

• A fibromuscular y-shaped tube attached to the terminal end of the mouth.
• Passes chewed food from the mouth to the oesophagus.
• Also a part of the respiratory system, allowing air to travel to the lungs.

Oesophagus

• A muscular tube that connects the pharynx.
• Supplies swallowed food along with its length.

Stomach

• Located on the left side of the abdominal cavity beneath the diaphragm.
• Stores food and provides time for digestion.
• Produces digestive enzymes and hydrochloric acid.
  • Mucous protects stomach lining
  • Digestive Enzymes breaks down polymeric macromolecules
  • HCL destroys microorganisms.

Small Intestine

• A thin, long tube (about 10 feet long) in the lower gastrointestinal tract.
• Located behind the stomach, occupying a maximum area of the abdominal cavity.
• Coiled with inner surface folds and ridges.

Large Intestine

• A thick, long tube (about 5 feet long) just beneath the stomach.
• Wraps over the superior and lateral edges of the small intestine.
• Absorbs water and hosts symbiotic bacteria that break down wastes.

Rectum

• The end of the large intestine where waste products are passed.
• Stores semi-solid feces, which are later eliminated through the anal canal via defecation.

Pancreas

• A large gland behind the stomach, connected to the duodenum.
• Releases digestive enzymes to complete chemical digestion.

Liver

• A triangular, reddish-brown accessory organ located to the right of the stomach.
• Produces bile, which aids in digestion of fat in the small intestine.

Gallbladder

• A small, pear-shaped organ located next to the liver.
• Stores and recycles bile.

Digestion Process

• The process begins in the mouth and ends in the small intestine.
• The large intestine absorbs remaining water and enables bacterial fermentation.

Steps of Digestion

1. Ingestion
2. Mixing and Movement
3. Secretion
4. Digestion
5. Absorption
6. Excretion

• The alimentary canal or gastrointestinal tract is a series of hollow organs and tubes which gradually digest food particles as they travel.

Ingestion

• The food first enters the food canal by the process of mastication(chewing).
• Salivary glands and the tongue help to moisten and lubricate food, before being pushed down into the food pipe.

Mixing and Movement

• It involves the process of lubricating and manipulating food and pushing it down the food with the process of peristalsis.

Secretion

• The stomach, small intestine, liver, and pancreas secrete enzymes and acids to aid the process of digestion.
• It involves the process of breaking down polymeric macro molecules into simpler substances.

Digestion

• The process of converting complex food particles into simpler substances with the process of secretion of different enzymes.

Absorption

• This process begins in the small intestine - the excess water in the indigestible matter is absorbed by the large intestines.

Excretion

• The process of removing wastes substances that haven't been subjected to digestion through the process of digestion.

The Respiratory System

• The respiratory system is the network of organs and tissues that help you breathe.
• The network includes your airways, lungs and blood vessels.
• The muscles that power your lungs are also part of the respiratory system.
• These parts work together to move oxygen throughout the body and clean out waste gases like carbon dioxide.
• The primary function of this system is to introduce oxygen into the body and expel carbon dioxide from the body.

Features of the Respiratory System

• Energy

• Oxygen

• Glucose molecules

• Energy is generated by the breakdown of glucose molecules in all living cells of the human body.

• Oxygen is inhaled and is transported to various parts and are used in the process of burning food particles (breaking down glucose molecules) at the cellular level in a series of chemical reactions.

• The obtained glucose molecules are used for discharging energy in the form of ATP- (adenosine triphosphate)

Respiratory System Parts and Functions

• Nose
• Pharynx
• Larynx
• Trachea
• Bronchi
• Lungs

Nose

• Humans have exterior nostrils, which are divided by a framework of cartilaginous structure called the septum.
• Tiny hair follicles that cover the interior lining of nostrils act as the body’s first line of defence against foreign pathogens.
• Furthermore, they provide additional humidity for inhaled air.

Pharynx

• The nasal chambers open up into a wide hollow space called the pharynx.
• It is a common passage for air as well as food.
• It functions by preventing the entry of food particles into the windpipe.

Larynx

• Two cartilaginous chords lay the framework for the larynx. It is found in front of the neck and is responsible for vocals as well as aiding respiration.
• Hence, it is also informally called the voice box.
• When food is swallowed, a flap called the epiglottis folds over the top of the windpipe and prevents food from entering into the larynx.

Trachea

• The trachea or the windpipe rises below the larynx and moves down to the neck.
• The walls of the trachea comprise C-shaped cartilaginous rings which give hardness to the trachea and maintain it by completely expanding.
• The trachea extends further down into the breastbone and splits into two bronchi, one for each lung.

Bronchi

• The trachea splits into two tubes called the bronchi, which enter each lung individually.
• The bronchi divide into secondary and tertiary bronchioles, and it further branches out into small air-sacs called the alveoli.
• The alveoli are single-celled sacs of air with thin walls. It facilitates the exchange of oxygen and carbon dioxide molecules into or away from the bloodstream.

Lungs

• Lungs are the primary organs of respiration in humans and other vertebrates
• The surface area is between 50 to 75 square meters.
• Humans have a pair of lungs, which are sac-like structures and covered by a double-layered membrane known as pleura.
• The primary function of the lungs is to facilitate the exchange of gases between the blood and the air. The right lung is bigger and heavier than the left lung.

Respiratory Tract

• External Nostrils
• Nasal Chamber
• Pharynx
• Larynx
• Epiglottis
• Trachea
• Bronchi
• Bronchioles
• Alveoli

Function of Human Respiration System

• Inhalation and Exhalation
• Exchange of Gases

Alveoli

• Oxygen and carbon dioxide are exchange through microscopic sacs.

Olfaction

• During inhalation, when the air enters the nasal cavities, some chemicals present in the air bind to it and activate the receptors of the nervous system on the cilia. The signals are sent to the olfactory bulbs via the brain.

The Lymphatic System

• The lymphatic system is a complex network of tubes, tissues, and organs that is a part of the circulatory system in the vertebrate body.
• Lymphatic system contains Tubes, Tissues and Organs.

Functions of Lymphatic System

• Immunity

• Fluid Balance Support

• As a vital part of your immune system, your lymphatic system protects you from infection and destroys old or abnormal cells your body doesn’t need.

• Lymphatic system functions also include maintaining normal fluid levels in your body and absorbing fats and fat-soluble vitamins so they can make their way into your bloodstream.

• Most nutrients can travel through tiny openings (pores) in the walls of your capillaries, and your body can then absorb and use them.

• But certain fats and other molecules are too large to travel in this way. Your lymphatic system collects fluid from your intestines that contains these molecules and transports it back to your bloodstream.

Anatomy of Lymphatic System

• White blood cells (lymphocytes) that the lymph transports combat infections.
• The bean-shaped glands called lymph nodes regulate and cleanse the lymph as it filters through them.
• They remove the cancerous and damaged cells by filtration.
• The thymus gland, a lymphatic and endocrine gland, is located behind the sternum.
• It secretes hormones and is essential for immunological T cell development, maturation, and differentiation.
• The tonsils generate lymphocytes and antibodies. They can provide defence against ingested and inhaled foreign particles.

Lymphatic System Organs

• Bone Marrow

• Thymus

• Lymph Nodes

• Spleen

• Lymph

• Collecting Ducts

• Tonsils and Adenoids

• Lymphatic Vessels

• Mucosa-associated lymphoid tissue (MALT)

• There are 8 organs of Lymphatic system. Thymus promotes immune response.

• Lymph vessels transport fluids. (MALT) IS Mucosa- associated lymphoid tissue protection.

Urinary System

• Humans get rid of wastes from the body through the urinary system.
• The urinary system is functional in turning toxic substances into the urine, storing and carrying urine, and safely eliminating it from the body.

Function & Organs of Urinary System

• Kidneys filter blood and produce urine.
• The urinary system filters your blood to get rid of what your body doesn’t need.
• It eliminates extra water and salt, toxins and other waste products.

Organs

• Kidneys
• Ureters
• Urinary bladder
• Urethra
• Urinary sphincter muscles

Kidneys

• Kidneys are paired bean-shaped structures forming the core of the urinary system.

• They are situated on either side of the spine towards the back, just below the rib cage.

• The right kidney is somewhat lower compared to the left to accommodate the liver.

• The innermost layer formed by the smooth fibrous membrane.

• A layer of fatty tissue. the outermost layer comprising connective tissue holding the kidney to the abdominal wall.

Ureters

• Ureters penetrate the walls of the bladder from either side, which forms a U shape.
• The Ureters at the terminal of the U connect to the triangular-shaped section on the bladder base known as the trigone.
• As the kidneys turn the wastes into urine, muscles which line the ureter walls aid in pushing the urine to the bladder to store.
• Through the ureteral orifices (openings), the urine enters the bladder.
• The mucous membrane in the uret ers stores urine in the bladder and prevents it from moving back up towards the kidneys where it can cause an infection.

Bladder

• The muscular hollow bladder keeps urine till eliminated. It is positioned in the abdomen behind the pubic bone. At the base of the trigone, there is an opening to the urethra in the neck of the bladder, via which urine moves out of the body.

• Three Layers: Serosa, Detrusor Muscle, Mucosa.

• When the bladder is full, a signal is sent to the spinal cord to urinate.

• The bladder muscles relax during filling and contract during urinating.

Prostate

• Is seen only in males and the shape of the size of the walnut. The semen gets released via the penis at the time of ejaculation.
• Furthermore, the prostate protects the bladder from any infection.
• Its muscular fibres squeeze, helping to control the urine flow into the urethra.

Urethra

• The fine, muscular tube of the urethra connects the bladder to the outside, rendering a route for urine to exit the body.
• Male Urethra is 8 inches and female urethra is 1.5 inches. The short length makes it easier for urine to move back up in the bladder and source an infection.

Urinary Sphincter

• Prevents urine leakage between voiding.

Brain

• The brain is an essential organ. All of your emotions, sensations, aspirations and everything that makes you uniquely individual come from your brain.
• Brain regulates body's vital functions.

Parts of the Human Brain

• Cerebrum
• Cerebellum
• Brainstem

Cerebrum

• The cerebrum is the largest part of the brain.
• It consists of the cerebral cortex and other subcortical structures.
• The cerebrum is divided into four sections or lobes: Frontal lobe, Parietal lobe, Occipital lobe and Temporal lobe.

Cerebellum

• The cerebellum is the second largest part of the brain, located in the posterior portion of the medulla and pons. The cerebellum has the cerebellar peduncles, cerebellar nuclei, anterior and posterior lobes. It mainly responsible for coordinating and maintaining the body balance during walking, running, riding, swimming, and precision control of the voluntary movements,
• Two Parts: Outer grey cortex & Inner white medulla

Brainstem

• Your brainstem regulates many automatic body functions. You don’t consciously control these functions, like your heart rate, breathing, sleep and wake cycles, and swallowing.

Lobes of the Brain

• Typically, the dominant hemisphere is responsible for your speech and language functions. The cerebral hemispheres have distinct fissures, which divide the brain into lobes.

• Frontal Lobe

• Parietal Lobe

• Occipital Lobe

• Temporal Lobe

• The brain is composed of billions of interconnected neurons.

• Interprets vision (color, light, movement).

• Personality, behavior, emotions. Speech: speaking and writing (Broca’s area) .Body movement (motor strip). Interprets language, words. Sense of touch, pain, temperature(sensory strip).

• Understanding language (Wernicke’s area) and memory.
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The Human Heart

• The human heart is one of the most important organs responsible for sustaining life.
• It's the primary organ of your circulatory system.
• Main function: Move blood throughout your body. Controls the rhythm and speed of your heart rate and maintains your blood pressure.
• Heart has four chambers, including atria and ventricles.

Structure of the Heart wall

• Three Layers: Epicardium, Myocardium & Endocardium.

• The internal structure of the heart is rather intricate with several chambers and valves that control the flow of blood.

Chambers of the Heart

• Left atrium.
• Right atrium
• Left ventricle
• Right ventricle

Blood Vessels

• There are muscular wall tubes mainly involved in supplying oxygenated blood away, Veins supply deoxygenated blood to the heart , Arteries are muscular-walled tubes that supply oxygenated. Aorta is the largest of arteries that branches off to throughout