Teas Test Science Part 2 Flashcards
Neuromuscular system
The neuromuscular system incorporates the nervous system and the muscular system and affects every part of the body daily functions and drive for homestasis
Neurons pass information using an electrical nerve impulse. Info passes through hundreds of neurons much like a game of telephone until it reaches the final destination of a muscle for an action to be performed.
Muscle cells carry out their function by their ability to contract.
Nervous System
Is to gather information from the internal and external environment and communicate any necessary changes to the muscular system
Divisions of the Nervous System
The nervous system is divided into the Central Nervous System (CNS) and the Peripheral Nervous System (PNS)
CNS
Consists of the brain and spinal cord
The brain integrates sensory information received from the internal and external environment and assembles a motor response
The spinal cord is similar to a multilane highway system that connects the peripheral nervous system to the brain
PNS
consists of the extensive network of spinal nerves carrying sensory or afferent information towards the spinal cord and brain and motor or efferent information away from the brain and spinal cord.
The spinal nerves are the many side roads and alleys that go to every part of our body outside the CNS so the brain has access to everything that is going on in the body and can make decisions necessary to keep homeostatic balance via muscle reactions.
When a stimulus is processed in the CNS…
The peripheral motor nerves send efferent impulses to both somatic and autonomic divisions of the nervous system to carry out a response
Somatic division
The somatic division is voluntary and controls the skeletal muscles of the body
-we can control our own body and muscles for movement and what not
Autonomic Division
also known as visceral division is involuntary and controls the visceral or cardiac muscles of organ systems like the digestive and cardiovascular systems without our conscious planning.
-like when we swallow (somatic) we turn on the involuntary (autonomic) pathway for digestions.
Neurons and the nerve impulse
The information gathered, processed, and passed to muscles travels as electrical impulses of the nervous system along specialized cells called neurons.
Anatomy of a neuron
Includes a cell body, dendrites, and axons
Cell body
the main part of the cell containing the nucleus and most organelles and nerve fibers that extend from the body
Dendrites
are nerve fibers
Dendrites are receptor extensions that receive nerve impluses
Axons
are nerve fibers
is a long singular tail-like extension, which sends impulses from the neuron body to the branching axon terminal
Nerve Impulse travel
All nerve impulses travel in this one-way direction: from dendrites to the cell body and then down the axon.
A stimulus is picked up at the dendrites and sent through the cell body and along the axon to terminal branches.
Once the nerve impulse reaches the axon terminal it stimulates the release of chemical neurotransmitters into a gap structure known as the synapse. The synapse is the structure that allows neurons to pass signals on to other neurons, muscles, or glands. Sensory neurons carry afferent impulses towards the CNS, and motor neurons carry efferent impulses from the CNS out to muscles.
Spinal nerves
are bundles of nerve fibers axons and dendrites and therefore contain both afferent and efferent impulses.
when an efferent axon terminal synapses with a muscle cell, the stimulation of a muscle contraction can occur.
Muscles and the process of contraction
Muscles are fibrous tissue with the unique ability to shorten or contract to move body parts and then unflex
Muscles consists with a bundle of muscle fibers and these muscle fibers contain countless of smaller myofibrils
Myofibrils
Have two types of contractile protein filaments: the thinner actin and thicker myosin
These contractile protein filaments are arranged in overlapping bands. A sarcomere is the repeating contractile unit of a skeletal muscle and is delineated by these bands of myosin and actin filaments.
Contraction
When the axon terminal secretes the chemical neurotransmitter at the synapse of a neuromuscular junction, it stimulates the muscle to contract.
Contraction occurs when the thin actin filaments slide past the thicker myosin filaments, causing the sarcomere unit to shorten or contract.
-The myosin or the actin dont shorten themselves but the length of the sarcomere by sliding past one another
Relaxtion
ATP, the chemical energy of all cells, is used to cause the contraction and is also necessary for the relaxation of the muscle
Many muscle fibers must contract in a unified pattern to cause a fluid muscle contraction for movement of a body part.
Muscles and the somatic system
In the somatic system, the fine motor control used in hand and eye muscles requires connections of three to six muscle fibers per neuron
For powerful contractions of leg or arm movements there can be connections of 1000 muscle fibers per neuron
Muscles and the autonomic division
The autonomic division of the neuromuscular system controls the contraction and relaxation of visceral reflexes
The rate and depth of the heartbeat by cardiac muscles and the mechanical propulsions and breakdown of food through the digestive system are both examples of neuromuscular control by Autonomic nervous system
Disorders of the neuromuscular system
can involve both the nervous and muscle systems
muscle response to nerve impulse can be affected by an injury to the muscle and/or its supporting ligaments and tendons
ALS
the neuromuscular junction is compromised in a condition called amyotrophic lateral sclerosis also known as Lou Gehrig’s disease
The motor neurons degenerate and die, leading to loss of voluntary muscle movement
Muscular Dystrophy
is a group of genetic disorders in which abnormal genes interfere with the production of proteins needed to form healthy muscle
While the nerves are not affected in muscular dystrophy, muscles progressively degenerate and weaken. BOTH VOLUNTARY AND INVOLUNTARY MUSCLES ARE COMPROMISED unlike ALS
Severe Transecting Spinal Cord
Injuries affect communication between the brain and peripheral nerves and are significant not only to voluntary skeletal muscles that are effected in the somatic system but also to the muscles of the autonomic system and their subsequent control of their visceral reflexes
Cells of the reproductive system
Sex cells function is to pass on our genetic material to the next generation
These sex cells or gametes are different in the male and female. male (sperm) Female(eggs)
Both male and female by necessity have half the number of genetic material resulting from meiotic cellular reduction division
in sexual reproduction the uniting of the sperm and egg nuclei during fertilization recombines a full set of genetic material for the formation of a zygote and the development of a new individual species
Organs of the reproductive system (male)
The male reproductive anatomy is responsible for the production of sperm and transferring it to the female system.
Sperm is produced in paired gonads called tests and held in the scrotal sac or scrotum
Sperm
The scrotum hold sperm outside of the body which helps regulate the cooler temperature necessary for the sperm to mature
The sperm mature in the epididymis, a tightly coiled tube on the back of each testis
During sexual arousal, mature sperm are transported from the epidermis through the duct system of the vas deferens then passes through the prostate gland where nutrients and lubricating fluids are added by the prostate gland, seminal vesicle, and bulbourethral gland to create semen.
Once through the prostate gland, semsn enters the urethra of the penis (primary external sexual organ of the male)
Fertilizan can occur if the perm meets the egg in the female reproductive system by traveling through the cervix, the opening to uterus and continuing into the fallopian tubes where it can meet an ovum.
Female reproductive System
is mostly internal and is responsible for the production of female gametes, as well as the implantation and maintenance of the fetus after fertilization.
The female gonads are the paired right and left ovaries that contain hundreds of immature female gametes known as eggs or ovum. The ovaries are adjacent to the opening of a fallopian tube that is a passageway that leads into the uterus the normal site of implantation and fetal development.
Mature Ovum
is released from an ovary, it is swept into the fallopian tubes and travels toward the uterus.
If the egg meets with a sperm fertiziliation can result. The fertizilied egg will then continue traveling through the rest of the fallopian tube and enter into the uterus, where it will implant into the uterine endometrial lining.
Fetal development ensures and the fetus is maintained by exchange of nutrients and wastes between mother and fetus through a structure called the placenta until 40 weeks and the fetus is considered full-term. Labor contractions of the uterus and dilation of the cervix allow the baby to move from the uterus through the vaginal birth canal.
Hormonal control of reproductive system
There are several male and female hormones that are closely involved in regulation and correct functioning of the reproductive system
Pituitary gland is the master control gland in the endocrine system
Fsh and LH
At the onset of puberty, it secretes follicle stimulating hormone (FSH) and luteinizing hormone (LH)
In the male, FSH promotes the production of sperm and LH controls the production of the hormone testosterone
in the female, FSH stimulates appearance of sexual chasteristics too and the begging of the menstrual cycle.
Approx every 28 days, hormones of the female system cause cyclic maturation of ova along with changes in the uterine lining.
Graafian Follicle
an ovary contains many immature eggs, each in a fluid-filled structure called a Graafian Follicle.,
FSH and females
The secretion of FSH by the pituitary promotes the development of a follicle, triggering it to secrete the hormone estrogen and this causes a spike in LH.
The jump of LH causes ovulation(rupturing of the egg from the follicle). where the egg is swept into the fallopian tubes, where it can meet with a sperm for fertilization. After ovulation the empty Graafian follicle terns into corpus lute. The corpus lute secretes the hormone progesterone, which causes thickening of the uterine lining to support pregnancy. If fertilization and implantation do not occur the uterine lining will be shed in messes of the mesntrual cycle.
Integumentary System
The main organ of the integumentary system is the skin
accessory organs of the integumentary system protect the body, regulate temperature, and perform other vital functions
Structure of the integumentary system
Our skin, the integumentary is made of three layers and is imbedded with accessory structures such as glands, hair, and nails.
The three layers are the epidermis, dermis, hypodermis
Epidermis
the outer layer of skin
it consists of keratinized stratified squamous epithelial tissue.
cells migrate from the deeper region to the exterior surface of the epidermis as they age and they become more flattened, slough off, and are replaced by younger cells
Around hair follicles the tubes from which hair grows the epidermis dips down into the middle layer of the skin called dermis
epidermis is avascular so it lacks blood vessels
Dermis
is connective tissue rather than epithelial tissue
different from the epidermis because it contains capillaries and small blood vessels
also known as the cutaneous layer cuz cut a laceration at least deep enough to bleed from the blood vessels in the dermis
layer of skin where many accessory organs originate
Hypodermis
also known as subcutaneous layer is referred to the deepest layer of the skin
-two types areolar and adipose tissue and these tissues are highly vascular and below the hypodermics is the muscle layer
Hair
is an accessory structure generated by epithelial cells at the base of the hair follicles
Hair acquires oil from sebaceous glands that surround hair follicles
oil is known as sebum and it moisturizes both hair and skin, keeping the keratin flexible and water-resistant.
Wax
Is an accessory structure
sebum is produced by the ceruminous glands accessory structures only found in the dermis of the external ear canal
Sebum from ceruminous glands combines with dead epithelial cells to form cerumen aka wax
Apocrine Sweat Gland
Physically associated with the hair follicle
The secretion from these sweat glands also referred to as a scent glands that has an odor that may act as sex pheromone in humans
has higher concentration of fatty acids than other sweat so when bacteria use apocrine sweat as nutrients they quickly change its odor to one of rancid fatty acids that smell.
Eccrine Sweat glands
also known as merocrine sweat glands
Has different composition because unlike most other exocrine glands of the skin, eccrine sweat glands deliver their secretions directly to the external surface of the epidermis
main role is to thermoregulation so they are found throughout the dermis of the human body
Functions of the integumentary system
6 primary functions
- It removes metabolic wastes
- synthesizes vitamin D
- Is a communication and sensory tool
- provides protection to the body
- and is the main organ of temperature regulation
Temperature regulation
Uses two primary means for thermoregulation: perspiration and diameter changes of blood vessels.
there are temperature sensors or thermoreceptors in both the hypothalamus and skin that provide info to the hypothalamus which it uses to act as the body thermostat.
W
Body temp high
When the body temp is too high it stimulates cutaneous vasodilation that increases the blood vessels diameter in the skin and allows more blood to flow near the surface of the body, so that body heat carried by blood is transferred to the external enviornmnent
if cutaneous vasodilation is not sufficient to lower body temperature into homeostatic range the hypothalamus stimulates sweat production. as perspiration on the surface of the skin dries it lowers body temperature through evaporative cooling
Body temp low
Shivering is a response caused by the hypothalamus when the body is below its homeostatic temperature.
these fast alternating contractions of muscle occurs below the skin and within the skin arrestor pili muscles tense with chilling temerpatures and causes hair to bristle
the contraction of these cutaneous smooth muscles generates heat, which is trapped within the insulated airspace created when hairs stick up but its not that effective for humans like for mammals
More effective way is when the hypothalamus cause vasoconstriction in the skin.
Cutaneous vasoconstriction reduces the amount of blood traveling close to the surface of the body, thus decreasing heat loss through the skin
Protection
The external aspect of the innate immune system plays an obvious protection role and is the external aspect of the innate immune system
Cerumen, hair, and mucus trap particles that can contain pathogens
The epidermal water barrier maintained by sebum and keratin helps prevent the body from dehydration
Excretion of waste materials such as mineral salts and urea
Keratin
a tough protein made by epithelial keratinocytes, which helps to prevent the body from dehydration
Sebum
lactic and fatty acids in sebum and sweat encourage a low pH that inhibits growth of bacteria.
Sweat also contains antibacterial substances
Other functions of the integumentary system
In the skin, sensory receptors of the Nervous system are activated in response to stimuli that is perceived as sensations (heat, pressure, pain) so it acquires input from the external environment.
Skin and its accessory organs also an interface of output to the external environment, Skin flushing and blushing, the expressiveness of eyebrows, and body odor are ways the integumentary system generates messages for communicating with other people.
