Chapter 1 Anatomy

Anatomy

Form

Physiology

Function

mediastinum cavity

It contains the heart, thymus, esophagus, trachea, and major blood vessels that connect to the heart.

Specialized branches of anatomy focus on the diagnosis of medical conditions or the advancement of basic scientific research. These branches include the following:

Pathologic and Radiographic anatomy

Gross anatomy includes:

Systemic anatomy, Regional anatomy, Surface anatomy, Comparative anatomy, Embryology

oblique plane

The coronal, transverse and sagittal planes are at perfect 90 degree angles from one another. If a plane is cut at another angle, it is termed

transverse plane

also termed a horizontal plane, divides the body into top (superior) and bottom (inferior) parts.

Ventral body cavities

are lined by serous membranes unlike those of the posterior cavities

The human body is partitioned into two main regions,

axial, and appendicular regions.

abdominal cavity

contains most of the digestive organs along with the kidneys and most of the ureters.

posterior body cavity is subdivided into two enclosed cavities,

cranial, and vertebral cavities

Surface anatomy

focuses on both superficial anatomic markings and the internal body structures that relate to the skin covering them

visceral pericardium

forms the heart's external surface.

Pathophysiology

investigates the relationship between the functioning of an organ system and disease or injury to that organ system.

chemical level

is the simplest level involving atoms and molecules. Atoms are the smallest intact chemical units and molecules are combinations of atoms.

effector

is the structure that brings about the change to alter the stimulus. Its action attempts to bring the variable back into optimal homeostatic range, as dictated by the control unit.

control center

is the structure that interprets input from the receptor and initiates changes through the effector. It serves as the go between, integrating the other two components of the homeostatic system.

Histology

is the study of tissues

Systemic anatomy

studies the anatomy of each functional body system

Cytology

the study of body cells and their internal structure

the serous cavity

Between the parietal layer and visceral layer of serous membranes is a potential space, called

Physiologists examine the function of various organ systems, and typically focus on the molecular or cellular level to gain a complete understanding of the system's workings. These groups include the following:

Cardiovascular physiology, Respiratory physiology, Reproductive physiology, Pathophysiology

receptor, control center, effector

Components of Homeostatic Systems

Anatomic position description

In order to assume the position, the person stands erect and upright with their limbs at their sides, their palms facing anteriorly and feet held together but positioned in a 45-degree angle from one another.

(a) Serous membranes are composed of two layers

a parietal layer and a visceral layer

Serous membranes secrete

a serous fluid that has an oily consistency. Its purpose is to serve as a lubricant that prevents friction when organs rub against one another in the ventral cavities.

1) Microscopic Anatomy

cannot be seen with unaided eye. It includes cytology and histology.

visceral layer

covers the external surface of the lungs

visceral layer

covers the external surface of the organ in the cavity.

Reproductive physiology

explores how the regulation of reproductive hormones can drive the reproductive cycle and influence sex cell production and maturation

pleural cavities

have two layers of serous membranes

axial region

includes the head, neck and trunk

Dorsal

is at the back side of the human body

organism

is the highest level human structural organization, comprised of all of the organ systems working in an integrated functional manner

pleural cavities two, serous membranes called

parietal layer and the other is the visceral layer.

Proximal

refers to a structure on the appendages. It is the structure closest to the point of attachment to the body trunk

Distal

refers to a structure on the appendages. It is the structure farthest away from the point of attachment to the body trunk.

Respiratory physiology

studies how respiratory gases are transferred by gas exchange between the lungs and the blood vessels, supplying the lungs among other things.

The quadrant system divides

the abdominal cavity into a right upper quadrant, right lower quadrant, left upper quadrant, and left lower quadrant.

The main two body cavities are

the posterior cavity and ventral cavity

four quadrants method

using the umbilicus as the central point and having imaginary transverse and midsagittal planes pass through the umbilicus.

Characteristics that Describe Living Things

Organization, Metabolism, Anabolism, Catabolism, Growth, Development (differentiation), Responsiveness, Regulation, Reproduction

Anatomists cannot gain a full appreciation of anatomic form without also understanding a structure's function. Physiologists cannot fully appreciate body functions without learning the form of the structures involved

a

pleural cavities

are located in the right and left sides of the thoracic cavity, they surround the two lungs

Homeostatic control systems

are separated into two broad categories based on whether the system maintains the variable within a normal range by moving the stimulus in the opposite direction, or amplifies the stimulus in the same direction

feedback loop

homeostatic system form a dynamic control system, known as

diagnosis

is a finding of the specific cause of the homeostatic imbalance.

Ventral

is at the belly side of the human body

pericardial cavity

is the potential space between the parietal and visceral pericardium.

peritoneal cavity

is the potential space between the visceral and parietal peritoneum, containing a lubricating fluid: serous fluid.

pelvic cavity

lies inferior to the horizontal plane, at the level of the superior aspects of the hip bones.

abdominal cavity

lies superior to this horizontal plane, at the level of the superior aspects of the hip bones

Disease

occurs when the body is unable to maintain a relatively stable internal environment: homeostatic imbalance

posterior body cavity

contains cavities that are completely encased in bone and are physically and developmentally different from the ventral cavity

Pathologic anatomy

examines all anatomic changes resulting from disease

Regional anatomy

examines all of the structures in a particular region of the body as a complete unit.

Comparative anatomy

examines similarities and the differences in the anatomy of different species.

Cardiovascular physiology

examines the functioning of the heart, blood vessels, and blood.

Anabolism

is a biochemical building process where small molecules are joined to make larger ones.

serous membrane

is a continuous layer of cells, as compared to the plasma membrane, which surrounds a single cell.

Computerized Tomography, CT scan

is a more sophisticated application of X-rays, producing multiple axial images of a body organ or region. The multiple images are processed and analyzed by a computer, thus producing a 3- dimensional image of a thin slice of the body region.

Reproduction

is a process that produces new cells for growth, maintenance and repair. The sex cells are responsible for developing a new living organism

Dynamic Spatial Reconstruction

is a special radiologic technique that provides three-dimensional images of body organs as they move

abdominopelvic cavity

is a subdivision of the ventral body cavity and is separated from the thoracic cavity by a flat dome-shaped muscle, known as the diaphragm.

Example of Negative Feedback

Temperature regulation

Anatomy and physiology initially may appear to be different sciences, but further reflection reveals that these two sciences are integrated, because form (anatomy) and function (physiology) are interrelated

a

The Body's Levels of Organization: Scientists group the body's components into an organized hierarchy of form and function.

a

The feedback loop operates in the following manner:

a stimulus is received by the receptor The receptor information is sent to the control center The control unit integrates the incoming input this dictates a change utilizing the effectors The effectors receive input from the control unit, effecting return of the body to homeostasis.

Homeostatic imbalance may sometimes occur due to a normal process, such as

aging

coronal plane

also termed a frontal plane, is a vertical plane that divides the body into front (anterior) and back (posterior) parts.

The View from Simplest to Most Complex Anatomists and Physiologists recognize several levels of increasing complex organization in humans. In increasing hierarchical order these levels include the following

chemical level, tissue level, organ level, organ system level, organism.

cellular level

consists of cells, which are the smallest living structures and serve as the basic units of structure and function. Interfaced between the chemical level and cellular level are the biochemical macromolecules (carbohydrates, lipids, proteins and nucleic acids) and the cellular substructures these macromolecules form, which are the organelles.

organ system level

contains organs that work together to coordinate activities and achieve a common function.

pelvic cavity

contains the distal part of the large intestine, the remainder of the ureter, the urinary bladder, and the internal reproductive organs.

The ventral cavity subdivisions

contains the thoracic and abdominopelvic cavities

nine compartment method

divides the abdominopelvic cavity into an umbilical region, epigastric region, hypogastric region, right hypochondriac region, left hypochondriac region, right lumbar region, left lumbar region, right iliac region, and left iliac region.

sagittal plane

divides the body into right and left halves. Since the body is intended to be bilaterally symmetrical, a cut down the middle of the head continuing down through the midline of the trunk (through the umbilicus) will divide the body into equal right and left sections, thus termed a midsagittal plane. If the body is divided into unequal right and left parts, it is simply termed a sagittal plane

Radiographic anatomy

investigates the relationships among internal structures that may be visualized by specific scanning procedures, such as the ultrasound, magnetic resonance imaging (MRI), or X-ray

Gross anatomy, also called macroscopic anatomy

investigates the structure and relationships of body parts that are visible to the unaided eye, such as the intestines, stomach, brain, heart, and kidneys.

Catabolism

is a biochemical breaking down process where large molecules are broken down into smaller ones

Anatomic position

is a common agreed upon point of reference used when describing the position of certain anatomical structures in the human body

Digital Subtraction Angiography

is a modified three-dimensional X-ray technique used primarily to observe blood vessels.

peritoneum

is a two-layered serous membrane that lines the abdominopelvic cavity. It also has a parietal layer and visceral layer.

plane

is an imaginary flat surface passing through the body. The planes of the body include the coronal, transverse, sagittal, and oblique planes

Sonography, termed ultrasound,

is an imaging method that transmits high-frequency ultrasonic waves into the body and receives them in order to produce an image of internal organs.

Regulation

is based in homeostasis. The ability to maintain a constant internal environment in the face of a changing external environment

organ level

is composed of human organs that are composed of two or more tissue types that perform specific, complex functions

appendicular region

is composed of the upper and lower limbs, which attach to the axial region.

tissue level

is comprised of groups of similar cells (similar embryonic origin) that collectively form common functions

cranial cavity

is formed by the bones of the cranium, and so it goes by the name endocranium.

vertebral cavity

is formed by the bones of the vertebral column, and houses the spinal cord.

pericardial cavity

is located within the mediastinum

abdominopelvic cavity

is subdivided into two smaller cavities, the abdominal cavity and pelvic cavity, by a horizontal plane at the level of the superior aspects of the hip bones.

Responsiveness

is the ability to sense and react to stimuli

receptor

is the body structure that detects changes in a variable, which is either the substance or process that is regulated. The change in the variable is the stimulus

Organization

is the complex hierarchical structuring of the body.

Embryology

is the discipline concerned with the developmental changes occurring from conception until birth

Growth

is the enlargement in the size of an organism

The visceral peritoneum

is the inner layer of this serous membrane, covering the external surfaces of most of the abdominopelvic organs.

The ventral cavity

is the large, anteriorly placed cavity in the body. Unlike the posterior cavity, the ventral cavity and its subdivisions do not completely encase their organs.

The parietal layer

is the outer layer that surrounds the internal surface of the thoracic wall

parietal pericardium

is the outermost layer of the serous membrane and forms the sac around the heart

parietal peritoneum

is the outermost layer of this serous membrane, lining the internal walls of the abdominopelvic cavity.

Development (differentiation

is the process whereby cells specialize to become more sophisticated for specific functioning, like nerve cells

Metabolism

is the sum of all chemical reactions in the body. Metabolism is subsumed into two interrelated processes, anabolism and catabolism.

Posterior

is toward the back surface.

Anterior

is toward the front surface

pericardial cavity

it encloses the heart in a two-layered serous membrane, called the pericardium.

(a) The parietal layer

lines the internal surface of the body wall.

mediastinum cavity

located in the median space in the thoracic cavity

thoracic cavity a subdivision of the ventral cavity , contains three cavities itself:

mediastinum cavity, pericardial cavity, and the pleural cavity

Negative feedback

moves the variable in the opposite direction

Positive feedback

moves the variable in the same direction

Magnetic Resonance Imaging, MRI

provides non-invasive images of soft body tissues, using a strong magnetic field and radio waves that alters the energy of protons in the nuclei of hydrogen atoms. Since hydrogen atoms are a main component of water molecules, soft tissues possessing higher water contents are viewed better than hard tissues, such as bone, having lower water contents.

set point

the variable is maintained with a normal level called

Positive Emission Tomography (PET scan)

uses radioactively labeled glucose molecules to analyze the metabolic state of a tissue at a given moment in time, thus determining which tissues are most metabolically active.