BODY STRUCTURE/HOMEOSTASIS Flashcards
(85 cards)
1
Q
Organ
A
Distinct structure of the body composed of two or more tissue types
2
Q
Organ system
A
Group of organs that work together to perform major functions in the body or meet physiological needs
3
Q
Organism
A
Living being that has a cellular structure and can independently perform all physiological functions necessary for life
4
Q
Integumentary system function
A
Encloses internal body structures and the site of many sensory receptors (eg. Hair, skin, nails)
5
Q
Skeletal system function
A
Supports the body and enables movement with the muscular system (eg. Cartilage, bones, joints)
6
Q
Muscular system function
A
Helps maintain body temperature and enables movement with skeletal system (eg. Tendons, skeletal muscle)
7
Q
Nervous system function
A
Detects and processes sensory information and activates bodily responses (eg. Brain, spinal cord, peripheral nerves)
8
Q
Endocrine system function
A
Secretes hormones and regulates bodily processes (eg. Thyroid gland, adrenal gland, pituitary gland pancreas, testes)
9
Q
Cardiovascular system function
A
Delivers oxygen and nutrients to tissues and equalizes temperature in the body (eg. Heart, blood vessels)
10
Q
Lymphatic system function
A
Returns fluid to blood and defends against pathogens (eg. Thymus, lymph nodes, spleen, lymphatic vessels)
11
Q
Respiratory system function
A
Removes carbon dioxide from the body and delivers oxygen to blood (eg. Lungs, trachea, nasal passage)
12
Q
Digestive system function
A
Processes food for use by the body and removes waste from undigested food (eg. Stomach, liver, gall bladder, large intestine, small intestine)
13
Q
Urinary system function
A
Controls water balance in body and removes waste from blood and excretes them (eg. Kidneys, urinary bladder)
14
Q
Male reproductive system function
A
Produces sex hormones and gametes and delivers gametes in females (eg. Epididymis and testes)
15
Q
Female reproductive system function
A
Produces sex hormones and gametes, supports embryo/fetus until birth, and produces milk for infant (eg. Mammary gland, ovaries, uterus)
16
Q
Why do anatomists standardize human body
A
To increase precision and avoid confusion. It allows us to provide a clear and consistent way of describing the human anatomy and physiology
17
Q
Anatomical position (4):
A
- The body is standing upright
- Feet are parallel and shoulder width apart
- Toes forward
- Upper limbs held out at each side with the palm forward
18
Q
Prone
A
Describes a face down orientation
19
Q
Supine
A
Describes a face up orientation
20
Q
Anterior/ventral
A
The front of the body or direction towards the front of the body
21
Q
Posterior/dorsal
A
The back of the body or direction towards the back of the body
22
Q
Superior/cranial
A
Above or higher than another part of the body
23
Q
Inferior/caudal
A
Below or lower than another part of the body
24
Q
Lateral
A
The side of the body or direction towards the side of the body
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Medial
The middle of the body or direction toward the middle of the body
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Intermediate
Between a more medial and more lateral structure
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Proximal
A position in a limb that is nearer to the point of attachment or the trunk of the body
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Distal
A position in a limb that is farther from the point of attachment or the trunk of the body
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Central
Towards the middle of a structure
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Peripheral
Towards the outer edge of a structure
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Superficial
Closer to the surface of the body
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Deep
Farther from surface of body
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Sectional planes (5):
- Sagittal plane
- Midsagittal plane
- Parasagittal plane
- Frontal/coronal plane
- Transverse plane
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Sagittal plane
Divides the body or an organ vertically into right and left sides
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Midsagittal plane
A sagittal plane that runs directly down the middle of the body and divides it into EQUAL right and left sides
36
Parasagittal plane
A sagittal plane that runs vertically away from middle of the body and divides it into two UNEQUAL right and left sides
37
Frontal/coronal plane
Divides the body or an organ into an anterior portion and a posterior portion
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Transverse plane/cross section
Divides the body or organ horizontally into upper and lower portions
39
Cavities
Membranes, sheaths and other structures that are used to separate the internal body into separate compartments. It is important for protecting delicate internal organs
40
What are the largest cavities
The dorsal (posterior) cavity and the ventral (anterior) cavity but abdominopelvic cavity is the LARGEST
41
Dorsal cavity (2):
- Consists of a cranial cavity that houses the brain, and the spinal cavity (or vertebral cavity) that encloses the spinal cord
- Brain and spinal cord are protected by the bones of the skull and vertebral column and are cushioned by cerebrospinal fluid produced by the brain
42
Ventral cavity (2):
- Consists of two main subdivisions (thoracic cavity and abdominopelvic cavity)
- Ventral cavity allows for significant changes in the size and shape of the organs as they perform their functions
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Thoracic cavity
Enclosed by the rib cage and contains the lungs and the heart (latter located in mediastinum)
44
Abdominopelvic cavity
Largest cavity in the body that is not physically divided by a membrane. However, anatomists distinguish between the abdominal cavity (division housing digestive organs), and pelvic cavity (division housing reproduction organs)
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Divisions of the abdominopelvic cavity by health care providers (9):
- Right hypochondriac: Liver, gallbladder
- Epigastric: Liver, stomach
- Left hypochondriac: Stomach, spleen
- Right lumbar: Ascending colon
- Umbilical: Transverse colon, small intestine
- Left lumbar: Descending colon
- Right iliac: Appendix, caecum
- Hypogastric: Lower small intestine, urinary bladder
- Left iliac: Proximal sigmoid colon
46
Serous membrane (serosa)
One of the thin membranes that cover the walls and organs in the thoracic and abdominopelvic cavity. It forms fluid filled sacs/cavities that cushions and reduces friction on internal organs when they move like when the lung inflates or heart beats
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Parietal layer
Membrane that lines the walls of the body cavity
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Visceral layer
Membrane that covers the organs
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What is in between the parietal and visceral layers
The cavity, a thin fluid-frilled serous space
50
Pleura
Serous membrane that surrounds lungs in pleural cavity
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Pericardium
Serous membrane that surrounds the heart in the pericardial cavity
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Peritoneum
Serous membrane that surrounds several organs in abdominopelvic cavity
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Homeostasis
Refers to the relatively stable set of conditions within an organism's internal environment
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Significance of homeostasis
Maintaining a healthy environment for living cells requires maintaining appropriate conditions in the extracellular fluids. The constancy of an internal environment is important in allowing chemical reactions to take place at rates necessary to maintain the body
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3 important conditions that must be met to maintain a constant internal environment:
- Maintaining proper concentrations of gases, nutrients, water, and salts
- Maintaining an optimum temperature of 37C for chemical reaction rates and proper protein shapes
- Maintaining an optimum pressure for the proper concentrations of various substances and the rates they move through the body
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Internal environment
Internal environment is the environment in which the cells are found
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Intracellular fluid
Fluid inside the cells (cytoplasm)
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Extracellular fluid
Fluid outside the cells in the body
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Plasma
Liquid portion of blood and functions to move red and white blood cells, platelets, nutrients, molecules, gases, electrolytes and wastes throughout circulatory system
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Interstitial fluid
Fluid that surrounds living cells within tissues
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Internal environment homeostasis (4):
- Homeostasis is maintained within the internal environment of the body
- It is the fluid inside the body but outside of cells
- Continually subjected to disturbances that if left unchecked could lead to illness or death
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Cells function in homeostasis
Responsible for controlling bodily activities and controlling the composition of the materials that surround them
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Cells are surrounded by __
Cells are surrounded by extracellular materials that is mostly fluid
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Stressor
Any stimulus that causes an imbalance in the internal environment
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External stressor
Stressors occurring outside the body (eg. lack of environmental oxygen, extreme environmental temperatures)
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Internal stressor
Stressors occurring inside the body (eg. rapid changes in blood pressure, changes in nutrient levels)
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Maintaining homeostasis (4):
- Requires the body continuously monitoring internal conditions
- Each physiological condition has a particular set point (the physiological value around which the normal range fluctuates)
- Normal range is a restricted set of values that is healthful and stable
- Feedback systems!
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Set point
Physiological value around which the normal range fluctuates
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Normal range
Restricted set of values that is healthful and stable
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Feedback system
Regulatory mechanism that monitors and adjusts a process based on the information received about its current state.
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5 components of feedback system:
- Sensor
- Control center
- Effector
- Response
- Normal range
- A SENSOR detects when the stressor/stimulus produces a deviation in a physiological value away from set point and reports to control center
- The CONTROL CENTER compares the current value to the normal range and if it deviates too much, then the control center activates an effector
- An EFFECTOR produces a response
- A RESPONSE causes return of the physiological value to its NORMAL RANGE
72
Negative feedback system (6):
- Mechanism that reverses a deviation from set point
- Body parameters maintained within normal range
- Functioning in body at all times
- The effected response works opposite to the stressor/stimulus
- Eg. Insulin lowers blood sugar when levels are high, and glucagon raising blood sugar when levels are low
- Eg. Elevated (heat gain) or decreased (heat loss) body temperatures maintained by negative feedback
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What happens when body temperature increases too much:
- Sensors detect the increase in body temperature and send to the control center (hypothalamus) of the brain
- The hypothalamus stimulates a cluster of brain cells called thermoregulatory center with THREE consequences
- The 3 consequences contribute to the response and lowers body temperature as heat is lost
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Hypothalamus
Control center of the brain
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Thermoregulatory center
Cluster of brain cells stimulated by the hypothalamus
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3 mechanisms for INCREASED TEMP
- Blood vessels dilating in the skin (effector); allowing more blood to flow to the surface and radiate heat
- Sweat glands activated (effector); increase production and secretion of sweat and evaporates and releases heat
- Depth of respiration increases (effector); increasing heat loss from the lungs
77
Decreased body temperature (3):
- Sensors detect the decrease in body temperature and send to the control center (hypothalamus) of the brain
- The hypothalamus stimulates a cluster of brain cells called thermoregulatory center with FOUR consequences
- The 4 consequences contribute to the response and increases body temperature as heat is produced
78
4 mechanisms for DECREASED BODY TEMPERATURE
- Blood vessels constricting in the skin (effector); Less blood to skin trapping heat in the core
- Skeletal muscles contract - shivering (effector); generates heat while using ATP
- Thyroid gland releases thyroid hormone (effector); increasing metabolic activity and heat production
- Adrenal glands release epinephrine (effector); glucose produced to increase metabolism
79
Beta cells (receptors)
Endocrine cells in the pancreas that detect excess glucose (stimulus/stressor) in the blood stream
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Beta cells (control center)
Responds to the increase blood glucose by releasing insulin
81
Insulin
Signals skeletal muscle fibers, adipocytes, and liver cells to take up the excess glucose
82
Positive feedback system (2):
- Intensifies a change in the body's physiological condition rather than reversing it
- Eg. Childbirth, blood clotting, urination
83
Childbirth as positive feedback
Enormous changes in the mother's body is required to expel the baby at the end of pregnancy and the events of childbirth must progress rapidly to a conclusion once begun to avoid risk. The extreme muscular work of labor and delivery are the result of a positive feedback system
84
Childbirth steps in positive feedback system (7):
- Contractions of labor (stimulus) push baby towards cervix
- Cervix contains stretch sensitive nerve cells that monitor the degree or stretching (sensors)
- The sensors sends messages to the brain that causes the pituitary gland (control center) to release oxytocin in blood stream
- Oxytocin causes stronger contractions of the smooth muscles in the uterus (the effectors) and pushes baby further down the birth canal
- This causes even greater stretching of the cervix (response)
- The cycle of stretching, oxytocin release, and the forceful contractions stops when the baby is born
- As the stretching of the cervix halts, it stops the release of oxytocin
85
Blood clotting in positive feedback
The body responds to the most immediate threat of excessive blood loss after a penetrating wound, and releases substances in the injured blood vessel wall that begins process of blood clotting until eventually sealing off the damaged area
