2. Thermoregulation refers to a process, it allows the body in maintaining a core internal
temperature. All the thermoregulatory mechanisms are designed for returning the human
body to a state of homeostasis. This state is an equilibrium state. Internal environment of
the body that is healthy falls under a window. An average person, mainly has a temperature
(baseline), between 37°C (98°F), and 37.8°C (100°F). Human body has some amount of
flexibility with reference to temperature. If the body temperature is in extremes, human
body cannot function properly. There are many factors that affect the temperature inside
the body, like more amount of time spent in heat or extremely cold weather conditions.
Increase in temperature is evident in fever, during digestion and exercise. Temperature
inside the body occurs in situations like use of alcohol, metabolic situations, and under-
functioning of thyroid gland. Hypothalamus refers to that section of the brain, which is
responsible for controlling thermoregulation. When the hypothalamus, actually is in a
position to sense internal temperature, (too high or low), it mainly send signals to organs,
glands, nervous system and muscles. By a number of ways, they respond and help in
returning the temperature to normal temperature. When internal temperature shows
changes, the CNS sensors, sends a message to the hypothalamus. By giving a response, it
sends a number of signals to various systems and organs in the body. When the human body
cools down, it can result in sweating and vasodilatation occurs. Sweat is released from the
sweat glands, it helps in cooling the skin, when it evaporates. All this helps in in lowering
the internal temperature. Also, the blood vessels placed under the skin widen. This process
leads to an increase in the blood flow to the areas of the skin which are cool, and away from
inner body that is warm. Heat is released from the body by means of heat radiation.
If the body has to get warm, mechanism included include vasoconstriction, the blood vessels
placed under the skin show narrowing. It helps in decreasing the flow of blood to the skin.
Organs, muscles, and the brain lead to production of heat in many ways. For an example,
muscles lead to production of heat if shivering happens. Another mechanism is hormonal
thermogenesis. The thyroid gland leads to release of hormones for increasing the rate of
metabolism. It increases the amount of energy that is produced by the body, and heat that is
produced. In short, the internal temperature rises or drops, outside of any normal range,
human body undergoes a number of steps for adjustments. This is a process which is known
as thermoregulation. It helps in avoiding/ recovering from dangerous situations, like
hypothermia. Insufficient heating in the home, drafty windows, and working outside
contribute to body pain, lowering of a body temperature, and colder fingertips.
Cardio Vascular System
Learning outcome 1:
Mitral valve
Atrioventricular valve.
P wave and PR segment
Aortic valve
3. QRS complex
Endocardium
Mitral valve
Superior vena cava
50-100 ml
Pulmonary veins
Learning outcome 2
Right atrium
Sino-atrial node
Ion channels
axon
axon terminal
right atrium
synaptic cleft
bundle of his
purkinje fibers
Right ventricle
Learning outcome 3
Diastole and systole are two phases of cardiac cycle. It refers to the sequence of alternate
contraction and relaxation of ventricles and atria, for pumping blood throughout the whole
body. It mainly consists of two periods. The first one during which muscles of the heart
relax and refill with blood, is known as diastole. It is followed by a phase of contraction and
blood pumping, known as systole. Diastole refers to ventricular filling, systole refers to
ventricular contraction. Both these events occur in left and right heart, with different
amount of pressures. The function of the ventricles is divided into 4 phases. They include
isovolumic relaxation, ventricular filling, isovolumic contraction, rapid ventricular ejection.
Cardiac cycle duration is inversely proportional to the rate of the heart. The duration of the
cardiac cycle, shows an increase when the heart rate decreases, whereas on the other hand,
it reduces with an increase in the heart rate. When a normal heart rate beat at 75 beats per
minute, cardiac cycle last for 0.8 seconds. Under the resting conditions, systole is made up
of one third, and diastole is made up of two third of the duration of the cardiac cycle.
Mechanical events, in the heart, during cardiac cycle, include the arterial pulse, heart sound,
and volume and pressure changes in the right atrium which can be reflected in the ECG. The
ventricle in the heart, when they contract, due to depolarization, also the pressure inside
the ventricles increases rapidly. After the ventricular contraction is started, pressure in
ventricles exceeds atrial pressure, and semilunar valves do not open, as ventricular
pressure is low, then in the aorta and pulmonary arteries. When volume and the pressure
changes are taken in consideration, ventricles contract, and walls are closed, no blood can
4. be ejected. The pressure in the ventricles increases, without changes in ventricular blood
volume, it is known as isovolumic contraction. Ventricular blood volume equals the end
diastolic volume. The AV valve bulge backward into atria, due to an increase in the pressure
in ventricles. Such events cause the c waves in venous Pulse. Pressure in the arteries in
pulmonary and systemic circulation decrease constantly. In the ECG, depolarization mainly
spreads from AV node to septum, and both the ventricular walls, through Purkinje and
Bundle of His fibres. A ventricular depolarization, leads to QRS Complex in ECG. At the very
same moment, repolarization of atria causes and produces T wave in the ECG. Atrial T wave,
is invisible on the physiological ECG, as it is covered by a QRS complex.
During the phase of isovolumic contraction, appearance of a sound occurs. These sounds are
caused by AV valves vibration.
Central Nervous System
Learning outcome 1
Brain and spinal cord
Somatic and autonomic nervous system
Schwann cells
Sulci
Gyri
Dorsal column system
Sensory afferent pathway
Sympathetic nervous system
Parasympathetic division
Cerebrospinal fluid
Learning outcome 2
Frontal section
Projection fibers
Cortex
Brain stem
Commissural
Genu
Hemispheres
Lateral ventricle
Cerebrospinal fluid
Choroid plexus
Learning outcome 3:
5. Central nervous system is well protected than any other system/ organ in the body. The
main line of defence is the spinal column, and the bones of the skull. It creates a harder
physical barrier to injury. Spinal cord and the brain are covered by layers of meninges,
outer coverings like dura, arachinoid and pia matter. Dura matter is a fibrous layer, and is a
strong protective sheet that covers the whole of brain. It anchors to inner surface of
vertebral cavity and cranium. It is a membrane made up of thin fibrous tissue, it forms a
loose sac around the brain. Below the arachnoid matter, a space which is known as sub
arachnoid space, occurs, where a filamentous, thin meshwork forms the arachinoid matter,
it looks like a spider web. Adjacent to the brain surface, is pia matter, a fibrous thin
membrane which allows the superficial convolutions of the brain, it fits into indentations
and other grooves.
Dura mater, encloses entire central nervous system, and a major blood vessel which enters
vertebral cavity and cranium. It is attached directly to the bones inner surface, of the
cranium, and end of a vertical cavity. It is also made up of two layers, a layer which is more
superficial, and attached to the skull, it is known as periosteal layer, a layer which lies deep
to the first layer, also known as meningeal layer. All the 2 layers fuse together. Also in
certain regions of the brain, they separate and form a large space, which is filled with
venous blood which is known as dural sinuses.
Arachnoid mater, is deeper to subdural space, it lies in the middle of the meninges, known
as arachnoid matter. Such a layer is named for spider web projections, known as arachinoid
trabeculae, between Pia matter and this layer. It defines a sac-like enclosure, surrounding
the central nervous system. In subarachnoid space, trabeculae are present, and they filled
with circulating cerebrospinal fluid (CSF), arachnoid, they emerge into the dural sinuses,
known as arachnoid granulations, where the cerebrospinal fluid, filters back into the blood
for drainage from nervous system.
Pia matter, extend into every convulations in the central nervous system. Blood vessels
which cross the central nervous tissue (CNS) are between the nervous tissue and the Pia
matter.
Central nervous system is crucial to operation the body, any compromise in the spinal cord
and the brain function leads to CNS difficulties. A number of structures protect the brain,
Firstly, skull bones enclose and cover the brain. Below the skeletal structures, brain is
mainly protected by connective tissues, known as meninges, they support, stabilize,
surround, and partition the Nervous System. Brain provides a blood supply which is known
as blood brain barrier. The functions of these tissues are crucial to survival of an organism,
and the content of the blood and it cannot pass into CNS. For protecting the regions from
pathogens and toxins, which may be travelling through the practice team.
Skeletal System
6. Learning outcome 1:
Temper mandibular joint
Osteon
Epiphysis
Lunate and scaphoid
Diaphysis
Ligament
Secondary cartilaginous joint
Tendon
Flat bone
Mesenchymal stem cells
Learning outcome 2:
end
Diaphysis
Yellow bone marrow
endoosteum
Cartilage
Periosteum
Osteoblasts
Epiphysis
Epiphyseal
Ends
Learning outcome 3:
For mineralization of bone, calcium ions mainly are essential for mineralization of bone and
also for tooth health, regulation of heart, contraction strength, smooth and skeletal muscle
contraction, and regulation of conduction of nerve impulses. The normal levels of calcium in
the blood (10 mg/dl), when the body is not in a position to maintain such levels, individuals
experience hyper-hypocalcemia. The main element is calcium; it is not produced by other
biological processes. It can enter blood only by diet. Storage sites for calcium include bones.
Deposition of calcium in the human body takes place in bone, in the blood, when the levels
are high; also release of calcium occurs when levels in the blood drop extremely low. This
process gets regulated in the presence of Vitamin D, parathormone and calcitonin.
Parathyroid gland cells have receptors at plasma membrane for element calcium. In
situations, when calcium does not bind to these receptors, parathormone is released, and
stimulates osteoclastic proliferation; this demineralisation process helps in releasing
calcium into blood.
Para hormone leads to the synthesis of Vitamin D, it stimulates calcium absorption from any
7. of the digested food in the small intestine. In situations, where processes return and
Calcium levels return back to a normal level, there is sufficient calcium that binds with
receptors on the cell surface of the parathyroid gland, and the cycle of events tone of when
the levels of calcium are extremely high, stimulation of the thyroid gland occurs, which
leads to release of calcitonin and this inhibits osteoblastic activities.
When the calcium levels are very high, stimulation of thyroid gland occurs, it releases
calcitonin, this inhibits osteoblastic activities, and in turn stimulates the uptake of calcium
by bones, also leads to a decrease in the area of action of calcium by kidneys. All such
actions reduce the level of blood calcium levels. When these levels return to normal values,
thyroid glands stop secretion of calcitonin. Calcium homeostasis, which refers to
maintenance of blood calcium levels of 10 mg/dl, it becomes extremely critical, for normal
functions of the body.
It resolves the problems with blood coagulation, function of the nerves, muscle contraction,
and strength of the bones. It results in lethargy, sluggish reflexes and appetite loss, coma
and confusion. Homeostasis of calcium, occurs under the control of Vitamin D, urinary
system, parathyroid hormone, digestive and endocrine system.
Human body control the calcium blood levels by adjustment of the level of several
hormones. When calcium levels in blood are low, parathyroid glands release hormones
known as parathyroid hormone, which helps bones release calcium in blood. Thyroid gland
regulates the metabolism of the body, on the other hand, parathyroid gland regulate levels
of calcium and they have no effect on metabolism.
