Unit 1: Introduction to anatomy and physiology PDF

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Unit 1: Introduction to anatomy and physiology ...

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UNIT 1: INTRODUCTION TO ANATOMY AND PHYSIOLOGY Anatomy Study of the structure of the body parts with an emphasis on how it relates to function. Subdivisions: Gross Anatomy- bodily structures that can be observed without magnification. Surface anatomy- Is the external structure of the body and is especially important in conducting a physical examination of a patient. Systemic anatomy-is the study of one organ system at a time Regional Anatomy- is the study of multiple organ systems at the same time in a given region of the body Physiology The study of functions and relationships of body parts. Pathology- the study and diagnosis of disease through the examination of surgically removed organs, tissues (biopsy samples), bodily fluids, and in some cases the whole body (autopsy) Pathophysiology- mechanisms of disease⇒studying the unstable conditions that result when homeostatic balance is lost histology- the microscopic structure of tissues and organs. Histopathology- is the microscopic examination of tissues for signs of disease. Cytology (cell biology)- the study of cells. Embryology- the study of prenatal development of gametes (sex cells), fertilization, and development of embryos and fetuses 11 Major Body Systems and Overall Functions (SEE NEXT PAGE)

The six levels of organization of the human body from simple to complex: 1. Chemical (molecular) level: cell components are composed of molecules (are composed of at least 2 atoms.) 2. Cellular level: smallest units of an organism that carry out all the basic functions of life. 3. Tissue level: a mass of similar cells and cell products that forms a discrete region of an organ and performs a specific function. a. ⇒ 4 types: epithelial, connective tissue, nervous, and muscular 4. Organ level: structure composed of two or more tissue types that work together to carry out a particular function. *skin is the largest 5. Organ system level- is a group of organs that carry out a basic function such as circulation, respiration, or digestion. ⇒11 total 6. Organism level (body as a whole) – single, complete individual.

Anatomical Position: A reference posture that allows for standardized anatomical terminology. A subject in anatomical position is standing feet flat on the floor, arms down to the sidesk and the palms and eyes directed forward. Three directional planes: sagittal plane- extends vertically and divides the body or an organ into right and left portions. (A midsagittal plane passes through the midline of the body and divides it into equal right and left halves.) frontal (or coronal) plane- an anatomical plane that passes through the body or an organ from right to left and superior to inferior. Transverse (horizontal) plane- passes across the body of an organ perpendicular to its long axis; therefore, it divides the body or organ into superior (upper) and inferior (lower portions)

Directional terms: superior- describes a position above or higher than another part of the body properly. The orbits are superior to the oris. inferior- describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal column). The pelvis is inferior to the abdomen anterior or ventral- describes the front or direction toward the front of the body. The toes are anterior to the foot. Posterior or dorsal- describes the back or direction toward the back of the body. The popliteus is posterior to the patella . medial- describes the middle or direction toward the middle of the body. The hallux is the medial toe. Lateral- describes the side or direction toward the side of the body. The thumb (pollex) is lateral to the digits. proximal- describes a position in a limb that is nearer to the point of attachment or the trunk of the body. The brachium is proximal to the antebrachium. distal- describes a position in a limb that is farther from the point of attachment or the trunk of the body. The crus is distal to the femur. superficial- describes a position closer to the surface of the body. The skin is superficial to the bones. deep- describes a position farther from the surface of the body. The brain is deep to the skull.

Two major body cavities: ● dorsal body cavity ● ventral body cavity

* axial region of the body contains major cavities containing the internal organs or viscera ⇒line by thin serous membrane, that secrete a thin film of moisture similar to blood serum

Describe the dorsal body cavity according to: subdivisions: Both cavities are lined up by 3 membranes called the meninges which protect delicate nervous tissue from the hard protective bone that encloses it. cranial cavity- is enclosed by the skull and contains the brain. vertebral cavity (vertebral canal)- continuous with the cranial cavity, is a space about as wide as your finger that passes down the vertebral column (spine), containing the spinal cord. organs contained within: brain and spinal cord ⇒Membrane Meninges Describe the ventral body cavity according to: subdivisions: ***divided by a muscular sheet called the diaphragm thoracic cavity (pleural cavities, pleura, mediastinum, mediastinal septum)- is above the diaphragm, also divide into right, left, and median portions by a partition called the mediastinum (thick median partition that separates one pleural cavity from the other, contains the heart, great blood vessels, esophagus, trachea, and thymus) ***Pg 20 in text is confusing the heart is enveloped by a two-layered serous membrane called the pericardium. The right and left sides of the thoracic cavity contain the lungs, which are enfolded in another two-layered serous membrane, the pleura. Organs: Pleural cavities (2) - lungs, membrane: Pleurae Pericardial cavity- heart, membrane: pericardium Abdominopelvic cavity (abdominal and pelvic cavities, peritoneum, mesentery) - divided into abdominal cavity and pelvic cavity, although the two form one continuous space; not separated by a wall the way the abdominal and thoracic cavities are separated by the diaphragm; dividing line is the margin of the pelvic inlet. ⇒lined by a 2-layered serous membrane called the peritoneum. ⇒ outer layer lining abdominal wall=parietal peritoneum ⇒ posterior midline of abdominal wall turn inward =visceral peritoneum, suspending certain abdominal viscera from the body wall and covering their outer surfaces ⇒ space b/w parietal peritoneum & visceral peritoneum= peritoneal cavity ⇒ visceral peritoneum also called mesentery at points where it forms a membranous curtain suspending and anchoring the viscera and a serosa at points where it enfolds and covers the outer surfaces of organs such as the stomach and small intestines

Organs: Abdominal cavity: digestive organs, spleen, kidneys, membrane: peritoneum Pelvic Cavity: bladder, rectum, reproductive organs, membrane: peritoneum -

organs contained within lungs, heart, digestive organs, spleen, kidneys, bladder, rectum, reproductive organs,

Function of the diaphragm: - The diaphragm is a thin skeletal muscle that sits at the base of the chest and separates the abdomen from the chest. It contracts and flattens when you inhale. This creates a vacuum effect that pulls air into the lungs. When you exhale, the diaphragm relaxes and the air is pushed out of lungs The nine regions of the abdominopelvic cavity: RIGHT & LEFT HYPOCHONDRIAC: -

The right hypochondriac region contains the right portion of the liver, the gallbladder, the right kidney, and parts of the small intestine.

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The left hypochondriac region contains part of the spleen, the left kidney, part of the stomach, the pancreas, and parts of the colon.

EPIGASTRIC: -

Epigastric (above stomach) region contains the majority of the stomach, part of the liver, part of the pancreas, part of the duodenum, part of the spleen, and the adrenal glands. This region pushes out when the diaphragm contracts during breathing.

RIGHT & LEFT LUMBAR: - The right lumbar region consists of the gallbladder, the right kidney, part of the liver, and the ascending colon. - The left lumbar region consists of the descending colon, the left kidney, and part of the spleen.

UMBILICAL Contains the umbilicus (navel), and many parts of the small intestine, such as part of the duodenum, the jejunum, and the ileum. It also contains the transverse colon (the section between the ascending and descending colons) and the bottom portions of both the left and right kidney RIGHT & LEFT INGUINAL (ILIAC) - The right iliac region contains the appendix, cecum, and the right iliac fossa. It is also commonly referred to as the right inguinal region. Pain in this area is generally associated with appendicitis. -

The left iliac region contains part of the descending colon, the sigmoid colon, and the right iliac fossa. It is also commonly called the left inguinal region.

HYPOGASTRIC - The hypogastric region (below the stomach) contains the organs around the pubic bone. These include bladder, part of the sigmoid colon, the anus, and many organs of the reproductive system, such as the uterus and ovaries in females and the prostate in males.

Quadrants of the abdominopelvic cavity: ***two perpendicular lines intersecting at the umbilicus (navel) dividing the area into 4 regions normally used to describe the site of an abdominal pain or abnormality. ● right upper quadrant (RUQ) ● left upper quadrant (LUQ) ● right lower quadrant (RLQ) ● left lower quadrant (LLQ)

abdominal acromial antebrachial antecubital axillary brachial buccal carpal calcaneal cephalic cervical coxal cranial crural cubital cutaneous

deltoid palmar digital patellar facial pedal femoral pelvic frontal perineal gluteal plantar inguinal popliteal lumbar pubic mammary sacral manual scapular mental sternal occipital tarsal olecranal temporal oral thoracic orbital umbilical nasal vertebral Zygomatic

Define the term “homeostasis.” The ability of the body to maintain a relatively stable internal environment in spite of external stimuli. In a state of dynamic equilibrium Homeostatic mechanisms stabilize variables such as body temperature, blood pressure, body weight, electrolyte balance, and pH. Describe the components of a “feedback loop.” There are 3 components: Receptor- is a structure that senses a change in the body such as the baroreceptors that monitor blood pressure. The integrating (control) center- such as the cardiac center of the brain, processes this information, relates it to other available information (for example, comparing what the blood pressure is, with what it should be), and “makes a decision” about what the appropriate response should be. The effector is the cell or organ that carries out the final corrective action. The response is then sensed by the receptor and the feedback loop is complete.

NEGATIVE FEEDBACK LOOP (MECHANISM) A self-corrective mechanism that underlies most homeostasis, in which a bodily change is detected and responses are activated that reverse the change and restore stability and preserve normal body function. Example: blood pressure regulation- rise from the bed in the morning, gravity causes some of your blood to drain away from your head and upper torso ⇒ decrease head blood pressure imbalance detected by baroreceptors in large arteries near the heart ⇒ baroreceptors transmit nerve signals to brain (cardiac center) cardiac center responds by sending nerve signals to heart (speeds up) ⇒faster heart rate raises blood pressure and restores normal homeostasis.

APPLY: In older people this response is sometimes insufcient⇒ may feel dizzy when rising. Drop in blood pressure may result in decreased blood to the brain and this sometimes causes fainting ⇒ Suggestion: have the patient sit-up first before they completely rise and maybe offer them something to drink (to help regulate their blood pressure

POSITIVE FEEDBACK LOOP (MECHANISM) Is a self amplifying cycle in which a physiological change leads to even greater change in the same direction, rather than producing the self-corrective effects of negative feedback. ⇒ sometimes normal way of producing rapid change Example: During childbirth, head of fetus pushes on the cervix (neck of the uterus) and stimulates nerve endings⇒ nerve signals travel to the brain (stimulates pituitary gland to secrete the hormone oxytocin (travels in to blood and stimulates the uterus to contract) ⇒ causes the fetus to be pushed down, stimulating the cervix more ⇒ causing the positive feedback to repeat. ⇒labour contractions intensifies APPLY: Could childbirth as a whole be considered a negative feedback event? Discuss. Yes, childbirth could be considered as a homeostatic response to pregnancy that culminates in ending the pregnancy and returning the body to its more usually...