Lecture 1 Flashcards
Metabolism
Sum of all of the chemical reactions that occur within the body
Anabolism
Small molecules are joined together to form larger molecules
Catabolism
Large molecules are broken down into smaller molecules
6 organizational levels in humans
Chemical level: simplest; atoms and molecules
Cellular level: cells (formed from atoms and molecules)
Tissue level: 4 major types = epithelial (covers exposed surfaces and lines body cavities), connective (protects, supports, and binds structures and organs), muscle (produces movement), nervous (conducts nerve impulses for communication)
Organ level: organs (contain 2+ tissue types that work together to perform specific, complex functions)
Organ system level: contains multiple organs that work together
Organismal level: all body systems function interdependently
12 organ systems
- integumentary system: provides protection, prevents water loss and gains, synthesizes vitamin D, releases secretions, regulates body temperature, houses sensory receptors (ex. hair, nails, skin + associated glands)
- skeletal system: provides support and protection, site of hematopoiesis (blood cell production), stores calcium and phosphorus, provides sites for ligament and muscle attachments
- muscular system: produces body movement, generates heat when muscles contract
- nervous system: regulatory system that responds to sensory stimuli, and controls muscles and some glands, also responsible for consciousness, intelligence, and memory
- endocrine system: consists of glands and cell clusters that secrete hormones, maintain homeostasis of blood composition and volume, control digestive processes, and control reproductive functions
- lymphatic system: transports and filters lymph and may participate in an immune response
- cardiovascular system: consists of heart and blood vessels; heart moves blood through vessels inn order to distribute hormones, nutrients, gasses, and pick up waste products
- respiratory system: responsible for exchange of gases between blood and air in lungs
- urinary system: filters the blood to remove waste products and biologically active molecules, concentrate waste products in the form of urine, and expel urine from the body
- digestive system: mechanically and chemically digests food, absorbs nutrients, and expels waste products
- male reproductive system: produces male sex cells (sperm) and male hormones (testosterone)
- female reproductive system: produces female sex cells (oocytes) and hormones (estrogen and progesterone)
Anatomic position
Person stands upright with the feet parallel and flat on the floor, the upper limbs are at the sides of the body, and the palms face anteriorly, the head is level and the eyes look forward
Prone
Lying face down
Supine
Lying face up
Plane
Implies an imaginary flat surface passing through the body
1. Coronal plane/frontal plane: vertical plane that divides body/organ into anterior and posterior parts
2. Transverse plane/horizontal plane/cross-sectional plane: horizontal plane that divides the body/organ into superior and inferior parts
3. Midsagittal plane/median plane: vertical plane that divides the body into equal left and right parts
3.1 Sagittal plane/parasagittal plane: divides structure into left and right unequal portions
4. Obli
Section
Implies an actual cut or slice to expose the internal anatomy
Plane
Implies an imaginary flat surface passing through the body
1. Coronal plane/frontal plane: vertical plane that divides body/organ into anterior and posterior parts
2. Transverse plane/horizontal plane/cross-sectional plane: horizontal plane that divides body/organ into superior and inferior parts
3. Midsagittal plane/median plane: vertical plane that divides body/organ into equal left and right parts
3.1 Sagittal plane/parasagittal plane: divides into unequal left and right parts (infinite amount)
4. Oblique plane (minor): pass through a structure at an angle
Anterior
In front of; toward the front surface
ex. the stomach is anterior to the spinal cord
Posterior
In back of; toward the back surface
ex. the heart is posterior to the sternum
Dorsal
Toward the back side of the human body
ex. The spinal cord is on the dorsal side of the body
Ventral
Toward the belly side of the human body
ex. the umbilicus is on the ventral side of the body
Superior
Closer to the head
ex. the chest is superior to the pelvis
Inferior
Closer to the feet
ex. the stomach is inferior to the heart
Cranial/cephalic
Toward the head end
ex. the shoulders are cranial to the feet
Caudal
Toward the rear or tail end
ex. the buttocks are caudal to the head
Rostral
Toward the nose or mouth
ex. the frontal lobe of the brain is rostral to the back of the head
Medial
Toward the mid-line of the body
ex. the lungs are medial to the shoulders
Lateral
Away from the mid-line of the body
ex. the arms are lateral to the heart
Ipsilateral
On the same side
ex. the right arm is ipsilateral to the right leg
Contralateral
On the opposite side
ex. the right arm is contralateral to the left leg
Deep
Closer to the inside, internal to another structure
ex. the heart is deep to the rib cage
Superficial
Closer to the outside, external to another structure
ex. the skin is superficial to the biceps brachii muscle
Proximal
Closer to the point of attachment to trunk
ex. the elbow is proximal to the hand
Distal
Farther away from point of attachment to trunk
ex. the wrist is distal to the elbow
Intermediate
Between medial and lateral
Axial region
Includes the head, neck, and trunk
Forms the main vertical axis of the body
Appendicular region
Composed of the upper and lower limbs, which attach to the axial region
Abdominal region
Inferior to the thorax (chest) and superior to the pelvic brim of the hip bones
Antebrachial region
Forearm (the portion of the upper limb between the elbow and wrist)
Antecubital region/cubital region
Anterior to the elbow (so front of elbow)
Auricular region
Visible surface structures of the ear (so ear)
Axillary region
Armpit
Brachial region
Arm (the portion of the upper limb between the shoulder and the elbow)
Buccal region
Cheek
Calcaneal region
Heel of the foot
Carpal region
Wrist
Cephalic region
Head
Cervical region
Neck
Coxal region
Hip
Cranial region
Skull
Crural region
Leg (the portion of the lower limb between the knee and the ankle)
Deltoid region
Shoulder
Digital region/phalangeal region
Fingers or toes
Dorsal region/dorsum region
Back
Facial region
Face
Femoral region
Thigh
Fibular region
Lateral aspect of the leg
Frontal region
Forehead
Gluteal region
Buttock
Hallux region
Big toe
Inguinal region
Groin (sometimes used to indicate the crease or junction of the thigh with the trunk)
Lumbar region
The “small of the back” (the inferior part of the back between the ribs and the pelvis)
Mammary region
Breast
Manus region
Hand
Mental region
Chin
Nasal region
Nose
Occipital region
Posterior aspect of the head
Olecranal region
Posterior aspect of the elbow
Oral region
Mouth
Orbital region
Eye
Palmar region
Palm (anterior surface) of the hand
Patellar region
Kneecap
Pectoral region
Chest, includes mammary region
Pelvic region
Pelvis (region inferior to the pelvic brim of the hip bones)
Perineal region
Diamond-shaped region between the thighs that contain the anus and external reproductive organs
Pes region
Foot
Plantar region
Sole of the foot
Pollex region
Thumb
Popliteal region
Area posterior the knee (back of knee)
Pubic region
Anterior region of the pelvis
Radial region
Lateral aspect (thumb side) of forearm
Sacral region
Posterior region between the hip bones (basically right above buttcrack)
Sternal region
Anterior middle region of the thorax (chest)
Sural region
Calf (posterior part of the leg)
Tarsal region
Proximal part of the foot and ankle
Thoracic region
Part of the torso superior to thoracic diaphragm; contains the pectoral, axillary, and sternal regions
Tibial region
Medial aspect of leg
Ulnar region
Medial aspect (pinky side in anatomic position) of the forearm
Umbilical region
Navel
Vertebral region
Spinal column
Posterior aspect/posterior cavity/dorsal cavity
Contains cavities that are completely encased in bone
Physically and developmentally different from the ventral cavity
No serous membranes
Subdivided into 2 enclosed cavities:
1. Cranial cavity (endocranium): formed by the bones of the cranium, contains the brain
2. Vertebral canal: formed by the bones of the vertebral column, contains the spinal cord and beginnings of spinal nerves
Ventral cavity
It and its subdivisions do not completely encase their organs in bone
Subdivisions are lined with thin serous membranes
Partitioned into 2 cavities:
1. Thoracic cavity
2. Abdominopelvic cavity
Serous membrane
2 layers:
1. Parietal layer of serous membrane: typically lines the internal surface of the body wall
2. Visceral layer of serous membrane: covers the external surface of the organs within that cavity
Serous cavity: potential space between the two layers
Secretes serous fluid within serous cavity (consistency of oil and serves as a lubricant; reduces friction caused by movement of organs against each other and body wall)
Thoracic cavity (subdivision of ventral cavity)
Serous pericardium = two-layer serous membrane that encloses heart
-Parietal pericardium = outer layer of the serous membrane and forms the inner lining of the sac around the heart
-Visceral pericardium = covers the heart’s external surface
Sub-cavities:
-Pleural cavity = each surrounds a lung; the serous membrane of each pleural cavity is the pleura
-Pericardial cavity = surrounds the heart; serous cavity between parietal and visceral pericardium; contains serous fluid
-Mediastinum = median space between lungs; contains heart, thymus, esophagus, trachea, and major blood vessels that connect to heart
Abdominopelvic cavity
Consists of:
-Abdominal cavity: contains most of digestive system organs (stomach, spleen, liver, gallbladder, small intestine, most of large intestine), kidneys, most of ureters
-Pelvic cavity: contains distal part of large intestine, remained of ureters and urinary bladder, and internal reproductive organs
Peritoneum = two-layered serous membrane
-Parietal peritoneum = outer layer; lines internal walls of abdominopelvic cavity
-Visceral peritoneum = inner layer; covers external surfaces of most abdominal and pelvic organs
Peritoneal cavity = serous cavity between these membranes; contains and is lubricated by serous fluid
Abdominopelvic regions
9 compartments in the shape of tic tac toe board (3x3 - written in order of left to right, top to bottom)
1. Right hypochondriac region
2. Epigastric region
3. Left hypochondriac region
4. Right lumbar region
5. Umbilical region (center)
6. Left lumbar region
7. Right iliac region
8. Hypogastric region
9. Left iliac region
Homeostasis
Refers to the ability of an organism to maintain a consistent internal environment in response to changing internal or external conditions
Keeps the body functions inn a narrow range compatible with maintaining life
Homeostatic control systems (3 steps)
- Receptor: the body structure that detects changes in a variable (which is a substance or process that is regulated). Typically consists of sensory neurons (nerve cells)
- Control center: the structure that both interprets input from the receptor and initiates changes through the effector (sometimes same structure as receptor). Generally a portion of the nervous system (brain or spinal cord) or an organ of the endocrine system (ex. thyroid gland)
-When it involves the nervous system, it usually provides a quick means of responding to change
-When it involves the endocrine system, it usually provides a means of a more sustained response over several hours or days through the release of hormones - Effector: structure that brings about the change to alter the stimulus (it causes an “effect”). Most body structures can serve as effectors, although it is usually muscles or exocrine glands
Feedback loop (response of a homeostatic control system)
- Stimulus: changes in a variable that is regulated (ex. temperature, stretch in muscle)
- Receptor: structure that detects the stimulus (ex. sensory neurons in the skin, stretch receptors in muscle)
- Receptor sends input info to the control center (if receptor and control center are separate structures)
- Control center: structure (usually brain or endocrine gland) that integrates input and then initiates change through the effector(s)
- Control center sends output info to an effector
- Structure (ex. muscle or exocrine gland) that brings about a change to the stimulus
- Homeostasis is restored
Negative feedback system
Controls most actions in the body
System maintains the variable within a normal range by moving the stimulus in the opposite direction
Reverses a change in a controlled condition
Resulting action will always be in the opposite direction of the stimulus. In this way, the variable is maintained within a normal level (set point)
Variable is not constant over time, it fluctuates around the set point
If the stimulus increases, the homeostatic system causes a decrease in the stimulus until it returns to the set point
If the stimulus decreases, the homeostatic system causes an increase in the stimulus until it returns to normal
Positive feedback system
Amplifies the stimulus in the same direction
Strengthens or reinforces a change in one of the body’s controlled conditions
Stimulus is reinforced to continue in the same direction until a climactic event occurs
Following the climactic event, the body again returns to homeostasis
Because their end result is to increase the activity (instead of initially returning the body to homeostasis), these mechanisms occur much less frequently
Ex. breast feeding:
1. Stimulus: baby suckles at breast
2. Receptor: sensory receptors in the skin of the breast detect the suckling; send impulses to hypothalamus
3. Control center: hypothalamus signals posterior pituitary to release oxytocin
4. oxytocin is released
5. Effector: breast is stimulated to eject breast milk
6. breast milk is released
7. baby feeds and continues suckling (positive feedback)
Cytoplasm
Contains all the cellular components between the plasma membrane and the nucleus
Membrane-bound organelles
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Peroxisomes
Mitochondria
Endoplasmic reticulum
Has a continuous lumen (space within a tube)
Typically extends from the nuclear envelope to the plasma membrane and composes about 1/2 of the membrane within a cell
External surface serves as a point of attachment for ribosomes and various types of enzymes
Rough endoplasmic reticulum
ER with ribosomes attached
Attached ribosomes produce proteins that will be released from the cell, incorporated into the plasma membrane, and serve as digestive enzymes within lysosomes
Transport from the RER occurs when small, enclosed membrane sacs (transport vesicles) pinch off from the RER. They shuttle proteins from the RER lumen to the Golgi apparatus for further modification
Helps forms peroxisomes
Basics from table:
-Synthesizes proteins for secretion, incorporation into the plasma membrane, and as enzymes within lysosomes
-Modifies and stores proteins
-Helps form peroxisomes
-Forms transport vesicles for shipping of proteins to Golgi apparatus
Smooth endoplasmic reticulum
ER with no ribosomes
Carries out diverse metabolic processes that vary by cell type
Functions include synthesis, transport, and storage of different types of lipids; carbohydrate metabolism; and detoxification of drugs, alcohol, and poisons
Basics from table:
-Site of lipid synthesis
-Carbohydrate metabolism
-Detoxifies drugs, alcohol, and poisons
-Forms transport vesicles for shipping to Golgi apparatus
Golgi apparatus
Composed of several elongated, flattened, membranous sacs (cisternae)
Distinct polarity. 2 poles: cis-face is closer in proximity to the ER and the diameter of its flattened sac is larger compared to the trans-face
Within the lumen, molecules are modified
At the trans-face, secretory vesicles form and carry both the modified and newly formed molecules away from the Golgi apparatus for different fates
“Warehouse” center: molecules arrive at the receiving region (cis-face), are modified and packaged within the lumen (along with some new structures that are produced), and are then shipped out at the shipping region (trans-face)
Basics from table:
-Forms proteoglycans
-Modifies and stores protein (that was formed by RER)
-Synthesizes digestive enzymes for lysosomes
-Forms secretory vesicles for delivering components of the plasma membrane and releasing contents from the cell by exocytosis
Lysosomes
Small, membrane-enclosed, spherical sacs, which contain digestive enzymes that are immersed in acidic fluid
These enzymes are contributed to lysosomes as portions of the Golgi apparatus containing digestive enzymes pinch off to form vesicles, and these vesicles then fuse with the lysosome
Participate in digestion of unneeded or unwanted biological macromolecules
Digest structures of damaged organelles (autophagy)
When a cell is damaged or dies, enzymes from its lysosomes are eventually released into the cytosol, resulting in the rapid digestion of the molecule components of the cell itself (autolysis)
Lysosomal storage disease: extensive group of heritable disorders that are characterized by accumulation of incompletely digested biological macromolecules within lysosomes. Occurs because of mutations in the genes that code for one of the more than 40 different lysosomal enzymes
2 nicknames:
1. “Garbagemen” because of their “cleanup” activities of eliminating unwanted structures
2. “Suicide packets” because of their function in autolysis
Basics from table:
-Break down molecules within vesicles that enter cell by endocytosis, remove damaged organelles and cellular components (autophagy), and break down cellular components following cellular death (autolysis)
Peroxisomes
Small, membrane-enclosed, spherical sacs that contain over 50 different enzymes that vary by cell type
Usually smaller in diameter than lysosomes
Initially formed by vesicles first pinching off from the RER
First named based on their role in chemical digestion, which involves removal of hydrogen from a molecule with the accompanying production of hydrogen peroxide. The hydrogen peroxide is subsequently broken down into water and oxygen (by catalase enzyme). Breaks down fatty acids, amino acids, and uric acid
Basics from table:
-Break down molecules with hydrogen peroxide produced during the process
-Forms specific types of lipids (ex. plasmalogens, bile salts)
Endomembrane system
Extensive array of membrane-bound structures that includes the ER, Golgi apparatus, vesicles, lysosomes, and peroxisomes (not mitochondria)
The plasma membrane and nuclear envelope are also considered part of this membrane system
All of these structures are either directly attached to one another or connected through vesicles that move between them
Involved in various forms of metabolic processes that occur within a cell, and they provide a means of both transporting molecules within the cell and releasing molecules from the cell
Substances are also brought into the cell as new vesicles are formed by endocytosis
Mitochondria
Oblong-shaped organelles that have a double membrane with the folds of the inner membrane called cristae
The matrix, which is the inner region of a mitochondrion, contains a small, unique, circular fragment of (maternally inherited) DNA that has genes for producing mitochondrial proteins
Engage in aerobic cellular respiration to complete the digestion of glucose and other fuel molecules for the transfer of energy to synthesize ATP molecules, the cell’s energy currency
Number of mitochondria within cells increase by fission with greater demands for ATP production
Also function in apoptosis (programmed cell death)
Energy harvesting: digest organic molecules to produce ATP by aerobic cellular respiration
Non-membrane-bound organelles
Composed of either protein alone or protein and ribonucleic acid (RNA)
They include ribosomes, centrosomes, proteasomes, and the cytoskeleton
Ribosomes
Arranged in large subunit and small subunit (both together create a functional ribosome)
Large subunit = 3 hollow areas designed as the A, P, and E sites
Bound ribosome = attached to the external surface of the ER membrane to form RER. Used to synthesize proteins destined for export out of the cell, to become an integral part of the plasma membrane, or to serve as enzymes within lysosomes
Free ribosome = suspended within the cytosol. In general, all other proteins that function within the cell are synthesized by free ribosomes
Protein synthesis:
1. Bound ribosomes synthesize proteins destined to be incorporated into the plasma membrane, exported from the cell, or housed within lysosomes
2. Free ribosomes synthesize proteins for use within the cell
Centrosome
Contains a pair of perpendicularly oriented, cylindrical centrioles surrounded by protein that is amorphous (without a distinctive shape)
Paired centrioles are positioned perpendicular to each other with each composed of triplets of microtubules arranged in a circle
Proteasomes
“Garbage disposals” for unwanted protein
Major protein-digesting organelles located within both the cytosol and nucleus of cells
Degrade cell proteins through an ATP-dependent pathway
Ubiquitin = protein bound to a protein that is marked for destruction by the proteasomes
Cytoskeleton
Framework of diverse proteins that extend both beneath the plasma membrane and through the interior of the cell
Both support the cell and organizes the organelles
Formed by 3 separate types of protein molecules:
1. Microfilaments: smallest components; composed of globular actin protein monomers that are organized into 2 thin, intertwined protein filaments (actin filaments); provides internal structural support of the plasma membrane (including extensions called microvilli); a contractile ring of these proteins separates the two cells formed during cytokinesis
2. Microtubules: largest components; composed of globular tubulin protein monomers that are organized into hollow cylinders; may be elongated or shortened as needed by the addition or removal of tubulin monomers; arranged like railway tracks; extend to the core of both cilia and flagella
3. Intermediate filaments: intermediate in size; less flexible; extend across the inside of the cell and function as rigid rods to both support the cell and stabilize junctions between them; their protein composition differs (ex. keratin)
Cilia
Small, hairlike projections
Usually found in large numbers on the exposed surfaces of specific cells such as those that line portions of the respiratory passageways
The movement occurs through the microtubules within their core, a process that requires energy provided by the splitting of ATP molecules
Flagella
Similar to cilia, but they are longer and wider, and there is usually only one if present
Helps propel the entire cell
Ex. in humans = sperm
Movement occurs through the microtubules within its core
Micorvilli
Thin, microscopic membrane extensions
Shorter and narrower than cilia, more densely packed together, and lack powered movement
Supported by microfilaments
Actin proteins of the microfilaments are cross-linked into a dense bundle that serves as its structural core
Membrane junctions
Composed of both integral membrane proteins and peripheral membrane proteins
Located between adjacent cells to provide an orderly arrangement and coordinate their interactions
3 major types:
1. Tight junctions
2. Desmosomes
3. Gap junctions
Tight junctions
Composed of plasma membrane proteins that form strands or rows of proteins
Positioned like spot welds at the apical surfaces around the circumference of each of the adjacent cells
They serve to:
-Seal off intercellular space and prevent substances form passing unregulated between the epithelial cells
-Prevent the mixing of membrane proteins and lipids on either side of the junctions, therefore maintaining the polarity of the epithelium and basal surface
Desmosomes (adhesion junction)
Composed of several different proteins that bind neighboring cells
Protein plaque is located on the internal surface of the plasma membrane of adjoining cells
Protein filaments extend from the protein plaque through the plasma membrane of both neighboring cells
Intermediate filaments of the cytoskeleton anchored to each protein plaque
Hemidesmosomes = half a desmosome; anchor the basal surface of cells of the epidermis to the underlying basement membrane
Gap junctions
Composed of 6 integral plasma proteins (connexons) that form a very small fluid-filled tunnel or pore that extends across a small gap between adjacent cells
Provide a direct passageway for substances to move between cells
The flow of ions between cells through gap junctions allows the spread of electrical activity in cardiac muscle of the heart
Transcription
Convert DNA into mRNA
Translation
Convert mRNA into a protein
