NERVOUS, INTEGUMENTARY, AND DIGESTIVE SYSTEMS

ANATOMY OF THE NERVOUS SYSTEM

• Controlling and regulatory center

• Consists of brain, spinal cord, nerves, and ganglia

• Central Nervous System

• Peripheral Nervous System

• Somatic and Autonomous Systems

integumentary system

comprises the skin and its layers.

nervous system is responsible

Together with the endocrine system, responsible for regulating and maintaining homeostasis.

Central Nervous System

comprises the brain and the spinal cord

peripheral system

includes the sensory and motor nerves.

includes the somatic and autonomic nervous systems.

brain

cerebrum, cerebellum, and the brain stem or the medulla oblongata.

spinal cord

a continuation of the brain

responsible for transmitting messages between the brain and the body.

somatic nervous

responsible for transmitting signals from the brain to voluntary muscles

autonomic nervous system

responsible for the involuntary actions and is further divided into

the sympathetic nervous system that is responsible for the fight or flight response

and

the parasympathetic nervous system that slows down the body’s metabolism when needed.

sensory nerves

carry information from the body to the CNS

motor nerves

carry information from the CNS to the muscles.

PHYSIOLOGY OF THE NERVOUS SYSTEM

• Sensory

• Integrative

• Motor

Sensory systems

respond to stimuli by sending signals to the
CNS

integrative systems

(within the CNS) process and evaluate the sensory information in a process called integration

Motor systems

carry signals from the CNS to effectors, and makes sure that motor output is coordinated for efficient responses

sensory receptors

detect changes, called stimuli, which occur inside and outside the body.

They monitor such things as temperature, light, and sound from the external environment.

Inside the body, the internal environment, receptors detect variations in pressure, pH, carbon dioxide concentration, and the levels of various electrolytes.

Sensory input

converted into electrical signals called nerve impulses that are transmitted to the brain. There the signals are brought together to create sensations, to produce thoughts, or to add to memory; decisions are made each moment based on the sensory input. This is integration.

motor function.

Based on the sensory input and integration, the nervous system responds by sending signals to muscles, causing them to contract, or to glands, causing them to produce secretions.

Muscles and glands are called effectors because they cause an effect in response to directions from the nervous system.

Nerve cells

communicate using chemicals called neurotransmitters. In multiple sclerosis, the body’s immune system attacks myelin, a fatty substance forming a sheath around nerves.

Cerebrum

argest part of the brain and is divided into lolbes that control different functions, including emotion, behavior, memory formation, and bodily functions.

frontal, parietal, occipital, temporal

cerebellum

coordinates the body’s movements.

spinal cord

begins at the brainstem and continues down the spine where it is protected by the vertebrae.

consists of nerves that carry messages between the brain and the rest of the body.

multiple sclerosis

myelin sheath attacked

ANATOMY OF THE INTEGUMENTARY SYSTEM

Three layers - Dermis, epidermis, and hypodermis

Functions:

• Barrier

• Homeostasis

• Sensation

• Appearance

Skin

largest organ in the body

three layers, the epidermis, dermis, and the hypodermis, all three of which vary significantly in their anatomy and function.

regulates temperature and the amount of water released into the environment

first site of immunological defense.

sensation to touch, heat, cold, and pain by the actions of the receptors present in it.

endocrine functions

include the production of vitamin D with the assistance of UV light from the sun.

exocrine functions

include the production of vitamin D with the assistance of UV light from the sun.

ANATOMY AND PHYSIOLOGY OF THE DIGESTIVE SYSTEM

• Alimentary tact

• Accessory organs

• Abdomen

• Mouth

• Intestines

• Process of digestion

digestive system

tube running from mouth to anus

chief goal is to break down huge macromolecules such as proteins, fats, and starch, which cannot be absorbed intact, into smaller molecules such as amino acids, fatty acids, and glucose respectively that can be absorbed across the wall of the tube, and into the circulatory system for dissemination throughout the

alimentary tract

composed of the mouth, pharynx, esophagus, stomach, small and large intestines, rectum, and anus.

accessory organs

Associated with the alimentary tract are the following accessory organs: salivary glands, liver, gallbladder, and pancreas.

abdomen

large cavity that houses these organs of digestion and excretion.

second-largest cavity of the body and is divided into four quadrants

mouth

or oral cavity

first part of the digestive tract

receive food by ingestion, break it into small particles by mastication, and mix it with saliva.

lips, cheeks, and palate form the boundaries.

contains the teeth and tongue and receives the secretions from the salivary glands.

pharynx

tongue forces food through

esophagus

collapsible muscular tube that serves as a passageway between the pharynx and stomach

stomach

responsible for receiving the food and mixing it with gastric juices present in it.

small intestine

finishes the process of digestion, absorbs the nutrients, and passes the residue on to the large intestine.

chemical digestion

microvilli

liver, gallbladder, and pancreas

accessory organs of the digestive system that are closely associated with the small intestine.

large intestine

produces no digestive enzymes.

responsible for the absorption of water and electrolytes and the elimination of feces

anal canal

last 2 to 3 cm of the digestive tract is the anal canal, which continues from the rectum and opens to the outside at the anus.

stomach lining

protected from acid by a layer of mucus and bicarbonate. Stomach ulcers may occur when this layer is disrupted, resulting in painful inflammation.

pancreas

releases enzymes into the small intestine that help the breakdown of food.

both endocrine and exocrine functions. The endocrine portion consists of the scattered islets of Langerhans, which secrete the hormones insulin and glucagon into the blood. The exocrine portion is a major part and consists of pancreatic acinar cells that secrete digestive enzymes to break down the food.

liver

produces bile, which is stored in the gallbladder and is secreted into the small intestine. Bile carries toxins out of the body and contains substances that help absorb nutrients

largest gland in body

Secretion

Synthesis of bile salts

Synthesis of plasma protein

Storage

Detoxification

Excretion

Carbohydrate metabolism

Lipid metabolism

Protein metabolism, and

Filtering

salivary gland

produces saliva that in turn,

Has a cleansing action on the teeth.

Moistens and lubricates food during mastication and swallowing.

Dissolves certain molecules so that food can be tasted.

Begins the chemical digestion of starches through the action of amylase, which breaks down polysaccharides into disaccharides.

gallbladder

pear-shaped sac that is attached to the visceral surface of the liver by the cystic duct. The principal function of the gallbladder is to serve as a storage reservoir for bile, a yellowish-green fluid produced by liver cells, and it is responsible for breaking down the food.