Animal Anatomy and Physiology Flashcards

Flashcards on Animal Anatomy and Physiology

Homeostasis

Maintains a stable internal environment despite external changes.

Key internal conditions regulated by homeostasis

Temperature, pH, oxygen, carbon dioxide, glucose, salt.

Negative Feedback

Reverses changes to bring conditions back to normal.

Components of a negative feedback loop

Sensor, control centre, and effector.

Positive Feedback

Amplifies changes for short-term events with clear endpoints.

Organization of Animal Bodies

Cells form tissues, tissues form organs, organs form organ systems, which form an organism.

Major Tissue Types

Epithelial, connective, muscle, and nervous.

Function of Epithelial Tissue

Lines and protects surfaces.

Function of Connective Tissue

Supports, binds tissues (bone, blood, fat, tendons).

Function of Muscle Tissue

Enables movement (skeletal, smooth, cardiac).

Function of Nervous Tissue

Transmits signals to coordinate actions.

Epithelial Tissue Function

Covers external (skin) and internal (digestive, reproductive tracts) surfaces; Barrier against damage, dehydration, pathogens.

Connective Tissue Description

Supports and connects tissues and includes bones, cartilage, blood, fat, ligaments, and tendons.

Types of Muscle Tissue

Skeletal, smooth, and cardiac.

Nerve Tissue Function

Specialized for communication; Detects changes and sends electrical signals.

Major Organ Systems

Circulatory, respiratory, digestive, nervous, musculoskeletal, reproductive, endocrine, urinary, immune, integumentary, lymphatic.

Types of Cell to Cell Communication

Direct and remote.

Direct Cell Communication

Physical contact through gap junctions (cardiac cells synchronizing).

Remote Cell Communication

Chemical messages travel to target cells (synaptic, paracrine, endocrine signalling).

Synaptic Communication

Fast, specific communication between neurons using neurotransmitters across a synapse.

Paracrine Communication

Local, short-lived signalling affecting nearby cells (inflammation, immune response).

Endocrine Communication

Hormones released into the bloodstream, affecting distant target cells with correct receptors.

Hormone Classification by Chemical Structure

Peptide, modified amino acids, and steroid.

Hormone Classification How they act on cells

Binding to external receptors (peptides, modified amino acids) or internal receptors (steroids).

Examples of Peptide and Modified Amino Acids

Insulin, glucagon, norepinephrine, epinephrine.

Steroid Characteristics

Lipid-based, fat soluble; Enters cells, binds to internal receptors, influencing gene expression; Slower acting, longer lasting.

Examples of Steroids

Testosterone, progesterone, cortisol.

Functions of the Circulatory System - Transport

Gases (oxygen, carbon dioxide), Nutrients (glucose), Waste (metabolic byproducts), Hormones.

Functions of the Circulatory System - Regulation

Body temperature.

Functions of the Circulatory System - Defence

Circulates white blood cells and antibodies.

Functions of the Circulatory System - Wound Healing

Clot formation and tissue repair.

Structure Types of Circulatory Systems

Open and closed circulatory systems.

Open Circulatory System

Blood flows freely through cavities, bathing organs directly; Seen in some invertebrates.

Closed Circulatory System

Blood stays within vessels; Allows for more pressure control; found in mammals, livestock, and all vertebrates.

Open Circulatory System Function

Heart pumps hemolymph (blood-like fluid) through vessels into an open body cavity (haemocoel).

Where a Closed Circulatory System is Found

Found in all vertebrates, including livestock, and some invertebrates like earthworms.

Closed Circulatory System Function

Heart pumps blood through arteries, which branch into capillaries for nutrient and gas exchange; Blood returns to the heart via veins; Essential for animals with higher metabolic demands.

Double Circulatory System - Fish

Fish have a single loop system (heart → gills → body), limiting pressure.

Double Circulatory System - Amphibians and reptiles

Amphibians and reptiles feature partial separation of oxygenated and deoxygenated blood.

Double Circulatory System - Mammals, birds, and crocodiles

Pulmonary circuit: heart ↔ lungs; Systemic circuit: heart ↔ body; Maintains high pressure in the systemic circuit and low pressure in the pulmonary circuit.

Sinoatrial node (SA node)

Located in the right atrium and is the pacemaker for the heart.

Blood Components

Plasma, Red Blood Cells, White Blood Cells, Platelets.

Plasma Function

Carries dissolved substances and distributes heat.

Red Blood Cells Function

Carry oxygen using haemoglobin; lack a nucleus.

White Blood Cells Function

Immune defence.

Platelets Function

Clotting.

Blood Clotting (Coagulation)

Vasoconstriction reduces blood flow; Platelets form a temporary plug; Thrombin converts fibrinogen into fibrin, forming a mesh that traps cells and seals the cut.

Lymphatic System Function

Returns excess fluid and plasma proteins to the bloodstream; Plays a key role in immune defence by filtering toxins and pathogens via lymph nodes.

Respiration and Gas Exchange

Exchange of oxygen and carbon dioxide throughout the body.

Cellular respiration

Occurs inside cells, uses oxygen to break down glucose for energy.

Organismal respiration

Physical act of bringing oxygen into the body and removing CO2 (breathing).

Efficient Respiratory Surfaces - Key Features

Gases diffuse when dissolved in fluid; Thin: Reduces diffusion distance; Large Surface Area: More area for gas exchange; Ventilated: Constant exposure to fresh air/water to maintain gradient.

Simple Respiratory Systems

Direct diffusion through skin (e.g., flatworms).

Complex Respiratory Systems

Bulk flow, diffusion across membranes, circulatory system transport (e.g., mammals).

Respiratory System Types - Body Surface

Diffusion across the skin (worms, amphibians).

Respiratory System Types - Trachea

Insects use tubes to bring air directly to cells (no blood transport).

Respiratory System Types - Gills

One-way water flow (fish).

Respiratory System Types - Lungs

Two-way airflow (mammals, reptiles, some amphibians).

Gills (Fish) - Water Flow

Water enters mouth, passes over gills, exits through slits.

Lungs - Inhalation

Diaphragm contracts, ribcage expands, air drawn in.

Respiratory System of Birds

Unidirectional airflow via air sacs (no diaphragm).

Respiratory Systems in Mammals

Conducting portion: Nasal/oral cavities, pharynx, larynx, trachea, bronchi, bronchioles; Gas exchange portion: Alveoli.

Control of Breathing

Primary influence: CO2 levels in blood (not oxygen); High CO2 causes decreased pH, triggers increased breathing rate; Negative feedback loop: CO2 levels fall, respiration rate slows.

Nutrients

Substances organisms need to survive, grow, repair tissues, reproduce, and carry out metabolic functions.

Nutrients - Classification

Classified as structural (proteins, lipids), energy sources (carbohydrates, fats), or metabolic regulators (vitamins, minerals, amino acids, fatty acids).

Organism Classification - Autotrophs

Produce their own food through photosynthesis (e.g., plants).

Organism Classification - Heterotrophs

Consume other organisms for nutrients (e.g., animals).

Essential Nutrients

Animals can't synthesize and must obtain through their diet (e.g., essential amino acids, essential fatty acids).

Malnutrition

Occurs when diet lacks or contains excess nutrients, disrupting normal body function.

Malnutrition - Kwashiorkor

Inadequate protein intake, leading to swollen bellies.

Malnutrition - Marasmus

Severe deficiency in protein and energy, causing extreme thinness.

Malnutrition - Rickets

Lack of calcium and/or vitamin D, weakening bones.

Nutrient Overdose

Overeating or excessive supplements.

Digestion

Process by which the body breaks down food into smaller, absorbable components.

Five Major Steps of Digestion

Ingestion, Mechanical Digestion, Chemical Digestion, Absorption, Elimination.

Intracellular Digestion

Occurs within individual cells; Common in simple organisms like sponges and protozoans.

Extracellular Digestion

Takes place outside of individual cells in a specialized digestive chamber.

Tubular Digestive Tract

One-way tube from mouth to anus.

Vertebrate Digestive System - Carnivores

Large canines for gripping and tearing meat, sharp molars for shearing.

Vertebrate Digestive System - Herbivores

Broad, flat molars for grinding plant material; may lack upper incisors, using a dental pad instead; side-to-side jaw motion.

Ruminant Digestion

Four-chamber stomach (rumen, reticulum, omasum, abomasum) for breaking down fibrous plant material.

Bird Digestion

Stomach has two chambers: one for enzyme secretion (protein digestion) and a gizzard for grinding (often with grit or small stones).

Hindgut Fermentation

Food passes through the stomach and small intestine (sugars, proteins, fats absorbed); Undigested material moves to the hindgut (cecum/colon) for microbial fermentation.

Non-Ruminant Vertebrate Digestive System - Stomach

Mechanical churning and gastric secretions initiate protein digestion; gastrin regulates.

Non-Ruminant Vertebrate Digestive System - Small Intestine

Site of enzymatic digestion and nutrient absorption; Pancreas and liver contribute enzymes and bile.

Stomach (Non-Ruminant)

Pepsinogen (from zymogen cells) is converted to pepsin (by hydrochloric acid from parietal cells) to break down proteins.

Large Intestine

Absorbs water and consolidates waste; Hosts endosymbiotic bacteria that synthesize vitamins K and B.

Horse Digestion

Non-ruminant herbivores rely on microbial fermentation in the hindgut.

Excretion

Removal of metabolic waste.

Elimination

Removal of undigested food (faeces).

Nitrogenous Waste - By Species

Aquatic Animals (Fish): Excrete ammonia (NH3); Mammals: Excrete urea (CO(NH2)2); Insects, Birds, Reptiles: Excrete uric acid (C5H4N4O3).

Excretory Systems - Insects

Malpighian tubules remove waste from hemolymph, conserving water.

Kidneys (Vertebrates)

Excrete metabolic waste (urea); Regulate ionic concentration and pH of blood plasma; Maintain blood volume and adjust water content; Retain essential nutrients; Secrete hormones.

Human Excretory System

Ureters: Transport urine from kidneys to bladder; Bladder: Stores urine until expelled through the urethra.

Maintenance of Homeostasis - Excretory System

ADH: Increases water reabsorption in kidneys; Renin-Angiotensin System: Regulates blood pressure; Kidneys secrete erythropoietin to stimulate red blood cell production in response to low oxygen levels.

Adaptations to Aquatic Environments - Excretory System

Freshwater Fish: Gain water through osmosis, excrete large volumes of dilute urine, and actively uptake salts through gills; Saltwater Fish: Lose water through osmosis, drink seawater, and actively pump out excess salt through gills; produce small amounts of concentrated urine.

Neurons: Fundamental Units

Neurons receive, process, and transmit information via electrical signals.

Types of Neurons

Sensory neurons, Relay neurons, Motor neurons.

Signal Generation - Resting membrane potential

Inside of the cell is more negative (-40 to -90 mV).

Sodium-potassium pump

Actively transports 3 sodium ions out and 2 potassium ions in, using ATP.