Download Homeostasis and feedback loops

Topic 1 week 1 Learning objectives
Learning objective questions – Homeostasis and feedback loops
What does the term homeostasis refer to?
Homeostasis refers to the body’s ability to maintain a relatively stable internal environment by keeping
particular variables within narrow limits. Maintenance of homeostasis in an organism is extremely vital
and if this process is interrupted the body may be compromised resulting in death or illness.
How can the body maintain homeostasis?
The body maintains homeostasis through the regulatory systems within the body including the nervous
and endocrine system which form feedback loops to achieve a relatively stable internal environment
(homeostasis).
What is a feedback loop?
A feedback loop is a cycle of events by which a variable is continually monitored, evaluated, changed,
remonitered and revaluated to ensure it is kept within narrow limits.
What are the three basic components of a feedback loop?
The basic components of a feedback loop include (1) A receptor which detects any change in the
controlled condition and sends this to a (2) control centre which evaluates this change and sends a
signal to an (3) effector if action is required.
What is a negative feedback loop? How does it work?
A negative feedback loop is a response whereby a change in a specific variable is detected by the
receptor and this information about the change is sent to a nearby control centre which assesses this
change, informing an effector if action if required to return this variable (controlled condition) back to
its normal state. An example is if body temperature rises a negative feedback loop is used to return the
body to normal body temperature.
What is a positive feedback loop? How does it work?
A positive feedback loop is far less common than a negative feedback loop and involves a detection in a
controlled condition or variable by a receptor whereby this info is then sent to a nearby control centre
and this centre notifies an effector if action is required resulting in a further exaggeration of that
response, moving it away from normal levels. An example includes an increased release of the
hormone oxytocins during child birth.
What is a homeostatic imbalance? What can it cause?
Homeostatic imbalance is a breakdown in one or more systems of the body causing a defect in
functioning of that specific function this is seen in individuals who have diabetes as their blood glucose
levels are not kept within narrow limits. Homeostatic imbalance can cause a disease or disorder if
moderate but if severe death can result.
What is a disorder?
A disorder is defined as an abnormality of structure and/ or function.
What is a disease?
A disease can alter the structure and function of the body resulting in an impairment in normal
functioning.
What is the difference between “local” and “systemic” diseases?
Local diseases affects only a limited part of the body whereas a systemic disease is one that affects a
number of parts or even the whole body.
What is a sign?
As sign is objective, that is, it can be directly observed or measured including blood pressure or
presence of oedema.
What is a symptom?
A symptom is subjective, that is, it cannot be directly seen or measured but is a feeling, belief, value or
sensation such as anger, nausea and headache.
Learning objective questions – Anatomical Terms
What is the anatomical position?
The anatomical position is assumed whenever referencing any anatomical terminology and in this
position the person is standing with their arms by their sides with palms facing forward, feet facing
forward and flat on flood, head facing forward with eyes facing forward also.
What is a prone position?
The person is lying face down in the anatomical position.
What is a supine position?
The person is lying face upwards in the anatomical position.
What are the major regions of the body?
The major regions of the body are:
-
The neck supports the head and connects to the trunk
The head consists of the skull and the face
The trunk is made up of chest, abdomen and pelvis.
Each upper limb attaches to the trunk and consists of the shoulder, armpit, arms, forearm, wrist
and hand
-
Each lower limb attaches to the trunk and consists of the buttocks, thigh, leg, ankle and foot.
Why do we use directional terms?
They allow us to locate various body structures and help us accurately describe and communicate to
other health professionals.
What do superior (cephalic/cranial) and inferior (caudal) refer to?
Superior (cephalic/cranial) means towards the head for example the hips are superior to the ankles.
Whereas inferior (caudal) means further from the head for example the stomach is inferior to the
lungs.
What do anterior (ventral) and posterior (dorsal) refer to?
Anterior (ventral) means toward the front of the body for example the belly button is anterior to the
spine whereas posterior (dorsal) refers to towards the back of the body, the spinal cord if posterior to
the chest.
What do medial and lateral refer to?
Medial refers to something that is closer to the midline for example the pinky finger is medial to the
thumb whereas lateral refers to something that is further from the midline, the ear is lateral to the
nose.
What do proximal and distal refer to?
Proximal refers to something that is further from the attachment of a limb to the trunk for example the
shoulder is proximal to the wrist whereas distal refers to something nearer to the attachment of the
limb to the trunk for example the fingers are distal to the wrist.
What do superficial and deep refer to?
Superficial means towards or on the surface of the body for example the ribs are superficial to the
lungs. Whereas deep means away from the surface of the body for example the ribs are deep to the
skin of the chest and back.
What is does the term “plane” refer to?
Plane refers to an imaginary flat surface that passes through the body or body parts.
What is a sagittal plane?
A vertical line that divides the body into right and left sides.
What is the midline?
The midline is an imaginary line that divides the body vertically into two equal halves.
What is a mid-sagittal (median) plane?
A vertical line that divides the body into two equal halves.
What is a parasagittal plane?
A vertical line that divides the body into two unequal left and right sides.
What is a frontal (coronal) plane?
A vertical line that divides the body into front and back halves.
What is a transverse plane?
A horizontal line that divides the body into top and bottom halves.
What is an oblique plane?
A line that passes through the body on an angle that is not at right angles to other planes.
Learning objective questions – The body cavities
What are body cavities?
Body cavities are spaces located within the body that help to protect, separate and support the internal
organs.
Where is the thoracic cavity? What other cavities does it contain?
The thoracic cavity contains three smaller cavities including the pleural cavities, pericardial cavity and
medistinum.
Where is the pericardial cavity? What does it contain?
The pericardial cavity is in the thoracic cavity and it contains the heart.
Where are the pleural cavities? What do they contain?
The pleural cavities are fluid filled spaces that are on either sides of the thoracic cavity and each cavity
contains one lung each.
Where is the mediastinum? What does it contain?
The mediastinum is located in the thoracic cavity and it is connective tissue which separates the two
pleural cavities and it contains the heart, the oesophagus, trachea, thymus and several large blood
vessels.
Where is the abdominopelvic cavity? What cavities does it contain?
The abdominopelvic cavity extends from the diaphragm to the groin and it is surrounded by the
abdominal wall and the bones and muscles of the pelvis.
Where is the abdominal cavity? What does it contain?
Located inferior to the diaphragm and superior to the pelvic cavity and it contains the stomach, spleen,
gallbladder, small intestine and most of the large intestine.
Where is the pelvic cavity? What does it contain?
The pelvic cavity is located inferior to the abdominal cavity and it contains the bladder, portions of the
large intestine and the internal portions of the reproductive organs.
What are the abdominopelvic regions? Where are they located?
The abdominopelvic regions are a type of method used by anatomists and health professionals to more
easily locate organs within the abdominal and pelvic cavities. It divides the cavities into nine smaller
regions. (from left to right starting at top) right hypochondriac region, epigestric region, left
hypochondriac region, right lumbar region, umbilical region, left lumbar region, right inguinal region,
hypogastric (pubic region) and left inguinal region.
What are the abdominopelvic quadrants? Where are they located?
Also another method used to divide and locate organs. (from left to right starting at top) Right upper
quadrant, left upper quadrant, right lower quadrant and left lower quadrant.
What does the term viscera refer to?
Refers to all the organs located within both the thoracic and abdominopelvic cavities.
What are serous membranes?
Thin, slippery, double layered membranes which cover the viscera of the thoracic and abdominopelvic
cavities.
What are parietal layers?
Is the layer of double-sided serous membrane that lines the wall of the cavity.
What are visceral layers?
Is the layer of double-sided serous membrane that attaches to and covers the outside of the organs
within the cavity.
What is the serous fluid? What is its function?
A slippery fluid secreted by the serous membranes into the space between the two layers (i.e. parietal
and visceral which helps to lubricate and reduce friction between the two layers allowing the viscera to
slide around to some degree during body movements.
What are the visceral and parietal pleura?
The visceral pleura is the layer of double-sided serous membrane that attaches to and covers the
outside surface of the lungs whereas the parietal pleura is the layer of double-sided serous membrane
that is stuck to the inside of the chest wall.
What are the visceral and parietal pericardium?
The visceral pericardium is the serous membrane layers that covers the surface of the heart. Whereas
the parietal pericardium is the serous membrane layer that is stuck to the inside of the check wall.
What is the visceral and parietal peritoneum?
The visceral peritoneum is the serous membrane layer that covers the surface of the abdominal
viscera. Whereas the parietal peritoneum is the serous membrane within the abdominal cavity.
Where is the retroperitoneal space?
Organs such as the adrenal glands, kidneys and pancreas that are located between th peritoneum and
the posterior portions of the abdominal wall.
Learning objective questions – Introduction to Anatomy and Physiology
What is the study of anatomy?
The study of body structures and their relationship to each other.
What is the study of physiology?
The study of how the body normally functions in a non-diseased state.
Why study anatomy and physiology?
Because how parts of the body work (their physiology) and their structure (their anatomy) are
intimately related.
What are the six characteristics of living organisms?
1. Movement- all of the chemical processes that occur in the human body there are two main phases:
a. Catabolism- breaking down of molecules
b. Anabolism- the building of molecules
2. Responsiveness- refers to the bodies ability to detect and respond to changes occurring in the
internal and external environment.
3. Movement- refers to the motion of the whole body
4. Growth- refers to increase in body size due to increased number of cells
5. Differentiation- refers to the process by which cells become specialised for a specific function
6. Reproduction- can either refer to the growth of new cells for tissue growth and repair or the
production of a new individual.
What are the six levels of structural organisation in the human body?
1.
2.
3.
4.
5.
6.
Chemical level- atoms and molecules
Cellular level- cells
Tissue level- muscle tissue
Organ level- heart
Organ system level- cardiovascular system
Organism level- humans
What are the eleven systems of the human body?
1.
2.
3.
4.
5.
6.
7.
Integumentary
Endocrine
Cardiovascular
Skeletal
Respiratory
Nervous
Muscular
8. Lymphatic
9. Digestive
10. Urinary
11. Reproductive