3 systems of the body:
ENDOCRINE SYSTEM:
Thyroid Gland:
DESCRIPTION: A gland split in 2 parts (bilobed), each part on either side of the wind pipe, just below the Larynx
HORMONE : This secretes an iodine containing protein called thyroxine
FUNCTION: Stimulates growth in infants.
AILMENTS:
DUE TO UNDERSECRETION / HYPOSECRETION:
DUE TO OVRESECRETION:
SIMPLE GOITRE:
This ailment is caused due to swelling in the thyroid gland. it occurs due to insufficient iodine in our daily food.
Increased metabolic rate, increased heart beat, weight loss, and general restlessness
CRETINISM:
This ailment brings abnormal growth in an infant. It causes mental and physical retardation
MYXOEDEMA:
This ailment usually occurs in adults, when insufficient thyroxine is produced. It shows general sluggishness, with swelling on the face and palms.
Adrenal Gland:
DESCRIPTION: these glands are like caps over kidneys. each of these glands have 2 parts Central Medulla
Peripheral Cortex
Central Medulla
Peripheral Cortex
FUNCTION: This hormone comes in action when a person is in fear, stress, or anger. it is also known as the flight or fight hormone, as it makes these decisions. it provides extra strength to the body by increasing the heart beat, increases blood pressure, and an increased rate of respiration
HORMONE: this gland secretes a hormone named adrenaline
this part secretes the adrenaline hormone.
even though the cortex is a part of adrenaline, it doesn't secrete that. It secretes a number of hormones such as the cortisone
Pancreatic Gland:
HORMONE: This gland secretes 2 hormones, namely insulin and glucagon with the help of cells called islets of Langerhans
FUNCTION: INSULIN (i)converts extra glucose to glycogen which is then stored in the muscles and liver. (ii) stimulates cells to burn extra glucose to produce heat and energy to provide to the body (iii) causes cells to convert extra glucose to fat. GLUCAGON stimulates the breakdown of glycogen in the liver to glucose, thus, raising sugar levels in the body.
DESCRIPTION: This is mainly digestive gland even though it has a cluster of hormone secreting cells. (islets of Langerhans)
AILMENTS: Diabetes Mellitus, or more commonly known as diabetes, is caused due to high concentration of glucose in the body. from the previous statement it is clear that there is less insulin in the body, thus, the extra glucose. this is also the reason why diabetes patients take an insulin shot. in this case, the person excretes a lot of urine and feels thirsty due to loss of water (through urination). in some cases, there is over secretion of insulin resulting in less glucose level.
Pituitary Gland:
DESCRIPTION: This is a very small gland located below the brain. although it is really small, it secretes a number of important hormones and is also called the master gland
HORMONE: (i) Growth hormone regulates growth, especially in adolescent years. (ii) Thyroid stimulating hormone (TSH) simulates the thyroid gland to produce thyroxine. (iii) Follicle stimulating hormone influences the production of sperms in males and ova / eggs in females. (iv) Prolactin stimulates the breasts to produce milk after child birth
THE CIRCULATORY SYSTEM
The transport of nutrients and oxygen, ncluding the removal of wastes like carbon dioxide and metabolic wastes are carried out through blood by a transport system called circulatory system.
DEFINITION: A system of ductless glands, secreting chemical substances known as hormones is called endocrine system.
FLUIDS OF OUR BODY
Lymph
Tissue fluid
Blood
It is contained in the heart and blood vessels(arteries, veins, capillaries)
It is contained within the lymph vessels and lymphatic organs. Most of the tissue fluid enters another minute channel called the lymphatic system. The lymph flows in its vessels because of contraction of the surrounding muscles. on the way the lymph drains into lymph nodes where fresh lymph channels arise. these channels ultimately pour into major anterior veins close to the right auricle and then the circulation cycle begins again
It occupies the space between individual cells and is also known as the interstitial tissue. The plasma and leukocytes from the capillaries of these tissues leak out and bathe the cells. from here, cells absorb oxygen and other required substances, and in turn, give out carbon dioxide and other things as waste, back into it.
Blood always flows through blood vessels. Basically, in a closed manner, thus, this kind of vascular system is called closed vascular system
the heart, acts as a pump for blood. it receives and pushes the blood to and from the body
HEART: THE PUMPING ORGAN
DESCRIPTION: It is the size of ones folded fist and weighs around 225 to 340 grams. It is located in the center of the chest cavity, slightly tilted to the left.
FUNCTION: It's main function is to pump and receive blood to and from the body through blood vessels.
Types Of Blood Vessels:
The vertically divided heart is separated by a membrane called septum.
FEATURES: It is protected within a double layered membrane named pericardium with a fluid called pericardial fluid between the 2 layers. this feature protects it from jerks, shocks, or any mechanical stress.
Auricles are receiving chambers and ventricles are distributing chambers
The right auricle opens into the right ventricle and is separated by the tricuspid valve. this valve prevents the backflow of blood.
The left auricle opens into the left ventricle and is separated by the bicuspid valve. this valve prevents the backflow of blood
Veins:
Capillaries:
Arteries:
These are the very fine blood vessels interconnecting veins and arteries. these are the principle locations where the exchange of oxygen, carbon dioxide and many other nutrients and waste substances between the blood and body tissue takes place.
These blood vessels bring back the blood to the heart, but there is an exception.
These blood vessels take the blood towards the rest of the body.
Blood Vessels Of The Heart:
Pulmonary Trunk:
Aorta:
Pulmonary Veins:
Coronary Artery:
Vena Cavae
Coronary Veins:
Bring oxygenated blood to the heart from the lungs
carries deoxygenated blood to the lungs from the right ventricle for oxygenation
carries oxygenated blood from the left ventricle to all parts of the body. (aorta is the biggest artery of the body)
The 2 large veins bringing deoxygenated blood to the right auricle. the superior vena cava brings blood from head / shoulders. the inferior vena cava brings blood from the rest of the body.
They bring back deoxygenated blood from the walls of heart to the right auricle
It distributes oxygenated blood to the walls of the heart. It is a branch of the Aorta.
BLOOD CIRCULATION
Deoxygenated blood from different parts of the body is received in the right auricle (through the inferior vena cava), at the same time, oxygenated blood comes into the left auricle from the lungs(through pulmonary veins)
Right auricle contracts and pumps blood into right ventricle, at this same time left auricle contracts and pumps blood into the left ventricle.
atrio-ventricular valves close with a sound after the ventricles are full and the semi lunar valves open.
right ventricle contracts pushing the deoxygenated blood into the pulmonary artery to the lungs for oxygenation. at this same time, the left ventricle contracts with great pressure sending blood to the aorta and then to all parts of the body.
semi lunar valves close after all the blood is sent into the arteries.
Composition:
Non-cellular part: it contains bout 94% of water. the rest of it is only proteins, carbohydrates, enzymes, antibodies, etc.
Cellular part: it contains leukocytes. blood platelets or RBCs are missing.
Functions Of Lymph:
(iv) lymphocytes and monocytes protect the body and also remove bacteria from the tissues. swellings we experience during a burn is due to the lymph localizing the infection as to not spread it to the whole body.
(ii) Drains metabolic wastes from the fluid tissue adn returns proteins to the blood from tissue spaces.
(iii) Fats in the intestine are absorbed through lymph vessels.
(i) Supplies nutrition and oxygen to those parts where blood cannot reach.
NERVOUS SYSTEM:
Blood Groups:
Karl Landsteiner in 1900 identified different types of blood groups in humans. these groups are based on differentiated proteins / antigens on the surface of RBCs. each antigen is given a specific letter which is also the letter of the blood type.
if the antigen in the body is 'A' then the blood type will be 'A'. if the antigen is 'B' then the blood type will be 'B'. if the RBCs have both A and B antigens then the blood type is AB. if the RBCs have neither A nor B, then the blood type is O.
A
B
AB
O (universal donor)
✔
❌
❌
✔
DONORS👉
❌
✔
❌
✔
A
B
AB (universal recipent)
O
✔
✔
✔
✔
❌
❌
❌
✔
RECIPENTS👇
👆👆👆👆👆👆👆👆👆👆Blood group compatibility in understood by the ABO system. from the above chart, we understand that (i) A can give to A and AB. (ii) B can give to B and AB. (iii) AB can only give to AB but can receive from any blood group. (iv) O can be given to all blood groups.
Heart Related Problems
Hypertension: This is nothing but a condition signifying high blood pressure. (blood flowing with greater force than normal). this condition can cause strain in the heart, and even damage blood vessels.
Heart Attack: it is a sudden interruption in the blood flow to the heart. it usually occurs due to a blood clot blocking the way of the blood. this causes a part of the heart to die and has a permanent damage. the heart still continues to function. symptoms include squeezing pressure in the chest. this pain can even spread beyond the chest to the neck, jaw, teeth, or arms. it can also cause shortness of breath, dizziness, sweating and nausea.
Palpitations: Sometimes you may experience your heart beating too fast, usually after exercise, but can also happen due to some kinds of foods, or even stress or anxiety. this is not serious but in rare cases can result in serious heart conditions.
Cardiac Arrest: this occurs when the heart suddenly stops pumping blood. the victims instantly go unconscious. some can even experience nausea or shortness of breath before a cardiac arrest. if not treated in minutes, it usually results in death
TAKING CARE OF YOUR HEART
Regular exercise and healthy food.
avoiding too much oily food
avoiding too much fast food
eating plenty of fibre containing foods.
avoid too much sweets
obesity or excessive weight is a very common problem
play outdoors
regular walking, jogging, cycling
The heart contracts and relaxes throughout one's entire life without stopping with the help of specialised cardiac muscles. the stimulation of these muscles is taken care of by electrical impulses originating from a node called sinoatrial node or SA node. it is located at the upper right corner of the right auricle. sometimes a mechanical device is used as a pacemaker in the heart due to damage in the SA node or if there is a problem in the electrical conduction system of the heart. this device is called the artificial pacemaker
valves that regulate the flow of blood from the ventricles to the arteries
Blood vessels of the heart
Vena Cavae: these veins bring deoxygenated blood from all parts of the body to the heart. inferior vena cava brings blood from the parts below the shoulders and the superior vena cava brings blood from the head and shoulders.
Pulmonary veins: They bring in oxygenated blood from the right and left lungs
Pulmonary Trunk: It arises from the right ventricle and carries the blood to the lungs for oxygenation. it later branches into left and right arteries going to the respective lungs.
Aorta: carries blood to the rest of the body after oxygenation.
Coronary Artery: carries blood to the walls of the heart after oxygenation
Coronary Veins: bring back deoxygenated blood from the walls of the heart to the heart.
Coordination: the interlinking of activities in a body to perform tasks is called coordination
Nervous Coordination: the coordination brought about by the nervous system which consistes of the brain, spinal cord, and nerves.
Chemical Coordination: the coordination brought about due to chemical substances called hormones
Functions Of Nervous System:
(ii) enables us to think, remember and reason
(iii) controls and harmonizes all voluntary muscular activities
(i) keeps us informed about our surroundings with the help of sensory organs.
(iv) regulates involuntary muscles eg. breathing, heart beat, etc.
Structural And Functional Part Of The Human Body
The nervous system is made up of special cells called nerve cells or NEURONS
Neuron:
Cyton: This is the main cell body, which also has a nucleus. it has extensions called dendrites which are cytoplasmic extensions of the cyton.
Axon: From the cell body comes out a long (apparently its called a process) called axon. it's length can vary from a few millimeters to 1 meter. The axons ends in branched filaments called terminal branches.
Types Of Neurons:
Sensory Neurons: carry impulses from sense organs to brain and spinal cord.
Motor Neurons: carry impulses from the brain and spinal cord to muscles and glands
Association Neurons: These transmit impulses from one neuron to another. (via synapses)
In synapses the axon terminal of one cell impinges on the dendrite of another. (its basically a small junction used for communication between 2 neurons). this takes place because of a special chemical called neuro-transmitter.
Nerve: a nerve is formed of a bundle of axons insulated in a tubular medullary sheath.
Sensory Nerve: contains sensory neurons.
Motor Nerve: contains only motor neurons
Mixed Nerve: contains both, motor and sensory neurons
2 Divisions Of The Human Nervous System
Central Nervous System (CNS): consists of brain(protected in the skull) and spinal cord(protected in the vertebral column).
Peripheral Nervous System: consists of nerves that are going to or coming from the CNS. These nerves are spread throughout the body. this has 2 divisions, somatic nervous system and autonomic nervous system.
Spinal Cord: extends from the medulla and runs almost the whole length of the back bone. the arrangement of the grey and white matter is reversed here. (inner portion is grey matter and outer portion is white matter)
Brain: It has 3 main parts. (i) Cerebrum, (ii) Cerebellum, and (iii) Medulla Oblongata
Somatic Nervous System: connects the CNS to the organs, muscles and skin.
Autonomic Nervous System: acts largely unconsciously and controls involuntary bodily activities. eg. heart rate, dilation etc.
Medulla oblongata: the lowest part of the brain. it stretches up to the spinal cord, its function is to control activities of internal organs like beating of the heart, breathing, peristalsis of alimentary canal etc. injury to this part may result in the death of a person.
Cerebellum: it is much smaller, located below the cerebrum. its main function is to balance the body and coordinate muscle activities. a drunk person cannot balance because alcohol affects the cerebellum.
Cerebrum: its the largest portion of the brain and is divided into 2 hemispheres called cerebral hemispheres (right and left). the outer surface is folded with ridges and grooves. it also is hollow. on the outside of the walls there is grey matter or the cyton of the neuron. on the inner portion of the wall there resides white matter or the axon of the neuron. this cerebrum controls intelligence, consciousness and will power.
NOTE: the ceribro-spinal fluid protects the brain from shocks and jerks
Functions Of The Spinal Cord:
ii conducts messages from skin and muscles to brain
i Controls reflexes below the neck
iii conducts commands from brain to muscles of the torso and limbs.
2 Types Of Nerves In The Somatic Nervous System:
Cranial Nerves: emerge from the brain. has 12 pairs - some are - i sensory ii motor iii mixed
Spinal Nerves: emerge from spinal cord. have 31 pairs. each pair has sensory nerve, they carry messages from sensory organs to spinal cord. motor nerves, do the opposite. they bring messages from brain to muscles and glands.
consists pair of chain of nerves and ganglia. located on either sides of the backbone. controls involuntary cations of internal organs. this operates through sympathetic and parasympathetic systems. these 2 systems are opposite(antagonistic) in their actions. sympathetic systems work when in fear (dilation of pupils, accelerates heart etc.)and the parasympathetic system does the opposite.
voluntary actions like gaming, studying etc.
involuntary actions like reflexes of your hand going away from the candle if it burns. or the flushing of tears when a particle falls into your eyes.
eye lids(motor)
Face and tongue(mixed)
optic nerves, to see.(sensory)
Reflex Action: the peripheral system and the spinal cord do stuff that don't involve the brain. like when you touch a burning candle after looking at the 'cool kids' and then realize that it really hurts, you take your finger away instantly. that, is reflex action.
The shortest pathway of a nerve impulse from receptor to affecter, making a reflex action possible, is REFLEX ARC
Types Of Reflexes With Examples
Natural(inborn) Reflex: no learning is required. its just naturally there.
Conditional Reflex: learning is required. typing on a keyboard, watering of the mouth etc. basically muscle memory(kind of)
Some Basic Terms In The Functioning Of Nervous System:
Response: activity that a body does due to stimulus
Receptors: The sense organs that receive the stimulus
Stimulus: Any change in the body that our body notices, and has a tendency to act to. eg. heat, cold, sharpness etc.
Impulse: a wave of electrical disturbance that runs through the nerves.
Effector: any muscle or gland where a response occurs
Heat is the stimulus
The neuron that receives the stimulus is the receptor
The sensation traveling through the nerve is impulse
Muscle of the hand receiving the command from the brain is the effector
The contraction of the muscle to withdraw the hand is called response